,31

HARVARD UNIVERSITY

Ernst Mayr Library

of the Museum of

Comparative Zoology

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GENERAL EVOLUTIONARY PATTERNS AND THE SYSTEM OF THE CLASS BIVALVIA

BY

SCARLATO AND YA . I. STAROBOGATOV
Zoological Institute
Academy of Sciences
Leningrad, USSR

IN

MORPHOLOGY, SYSTEMATICS AND PHYLOGENY OF MOLLUSKS

Transactions of the Zoological Institute
Academy of Sciences, USSR, Vol. 80, pp. 5-38, 1979

An edited translation of:

Osnovnye Cherty Evolyutsii i sistema Klassa Bivalvia

Morfologiya, Sistematika i Filogeniya Mollyuskov

Trudy Zoologicheskogo Instituta, Akademiya Nauk SSSR

Tom 80, pp. 5-38, 1979

BY

KENNETH J. BOSS AND MORRIS K. JACOBSON
Museum of Comparative Zoology
Harvard University
Cambridge, Ma. 02138

Special Occasional Publication
NO. 5
published by the
Department of Mollusks
Harvard University
Cambridge, Massachusetts 02138
1985

GENERAL EVOLUTIONARY PATTERNS AND THE SYSTEMATICS OF THE CLASS BIVALVIA

by

0. A. Scarlato and Ya. I. Starobogatov

Questions concerning the systematics of the class Bivalvia have
been recently the object of much discussion among malacologists . The
varied external shapes as well as the abundance of species and genera
combined with the comparatively monotypic internal organization have
long ago given birth to two opposing systems: one resting exclusively
on conchological features (and therefore especially attractive to
paleontologists), and the other based almost wholly upon a study of
the internal anatomical structures. Without going into the entire his-
tory of the systematics of the class, which has recently been done
(Nevesskaya, 1975), we must emphasize that in recent years there has
been noticeable narrowing of the gap between basically conchological
or basically malacological systems. Several modified systems, based
on both the internal and external features, have been proposed,
(Scarlato and Starobogatov, 1970, 1975; Nevesskaya, 1971). Further
refinements require a deeper analysis of the evolutionary changes in
the exoskeleton as well as in the internal organs. It is primarily
necessary to understand the functional significance of these changes,
and secondly, to explain which evolutionary processes were involved
with the establishment of the class, that is to say, to understand
the initial features which led to the adaptive radiation of the Bivalvia.

A detailed analysis of all the evolutionary changes in the Bivalvia
would "become the subject of an entire book. Thus, in this article we
intend to limit ourselves to several fundamental questions, especially
since we discussed the phylogenetic associations and early evolution of
the bivalves previously (Scarlato and Starobogatov, 1975) •

We place the Bivalvia in the subphylum Peltophora together with
the Aplacophora and Polyplacophora, since they all come from thus far
undetected ancestors common with the last named class (Minichev and
Starobogatov, 1975). The transition of such forms from a life on
rocks to softer substrates led to the necessity of protecting the
lateral portions of the body. Thus, the shell flexed sharply in two,
eventually dividing into two valves which are united dorsally by an
organic structure. The transverse muscular band is converted into
the anterior adductor muscle. Such primitive bivalves are disting-
uished from the present members of the class because l) they had a
head with pre-intestinal formations, 2) they were monomyarians , 3) the
dorsal margin of their valves were straight and lacked an umbo. The
transition of the primitive bivalves to contemporary bivalves is
bound up with the following: l) the shift of the formation of straight
dorsal margins to an early stage of ontogenesis, 2) the formation of
a second (posterior) adductor muscle, 3) the reduction of the head
and pre-intestinal formations and the development of strong labial
palps. The shortening of the straight dorsal margin, associated with
its occurrence in earlier ontogenetic stages, led to the formation of

the umbo. The development of the labial palp as a food catching organ
for the collecting of particulate matter was the origin of the widening
of the free anterior shell margin, the repositioning of the umbo back-
wards (in Muculana and similar forms — contrary to the usual rule —
the tentacles of the labial palps thrust themselves to the posterior
end of the shell). The ctenodont hinge type was formed as the hinge
margin was periodically raised and the perpendicular parts of the teeth
appeared later. The general features of such hinges are the formation
of radial elements as shell growth continues.

The transition from the superorder Protobranchia is characterized
by the transfer of features to the superorder Autobranchia associated
with the adaptation to a sedentary life style, made possible by
the formation of a byssus. This is shown in the universality of the
byssus type among the Autobranchia at one or another stage of ontogenesis.

The formation of the hinge was shifted to an earlier stage
of ontogenesis, and this fixed the number of radial elements in
the hinge (Fig. l). This led to the formation of a pre-heterodont
hinge, in which the number of teeth does not increase during
growth and there is only a single tooth along each radius. In
the food obtaining process, the labial palps are replaced by a
branchial filtering apparatus. Nutrient laden water begins to enter
the shell at its posterior end in response to the lengthening of
the free posterior margin, and the umbos move forward. There are
other reasons more closely related to life styles accounting for
the shift in the position of the umbos and the appearance of the

filtering apparatus (Stanley, 1975). The stomach appears — in
origin a large typhosole accompanied by an intestinal fissure; the
crystalline style and the sorting fields are formed and this gradually
led to the disintegration of both liver ducts.

Some lower Autobranchia were not content with a ciliated
water-moving apparatus and begin to make use of the muscles of
the branchial filaments for this purpose. The gills became septa
(a membraneous pump). Thus the superorder Septibranchia arises.
The primitive members were filter-feeders, but later they became
predators, and this led to the reconstruction of their stomachs,
specifically to the disappearance of the sorting apparatus, the
hypertrophy of the cuticular cover, and the restructuring of the
liver, which began to consist of only 2 diverticula.

Food gathering by means of the labial palps restricted the
radiation of the Protobranchia. Most members of this superorder
(order Nuculida) preserved features characteristic of mobile
Bivalvia — an oval or anterior-posterior ly lengthened shell, a mobile
foot with a flat sole, 2 adductor muscles, a nuculoid hinge con-
sisting of chevron-shaped teeth which grow in size in front of
and behind the umbo, and primitive double ctenidia with lamellae
directed centrally from the axis. The labial palps — the main food
gathering organ — and the ligament primarily undergo changes.
Only several more primitive members : Radiidens , Lametila, Phaseolus ,
for example, preserve the phaseoloid hinge. On the other hand, the
cuticular cover of the stomach in Radiidens is more strongly developed

than in Nucula or Nuculana and a muscular crest is absent; a
continuance of a small typhosole and an infaunal burrowing life
style, characteristic for the order Solemyida, led to a lengthening
of the shell and restructuring of the hinge, which in Nucinellidae,
Manzanellidae, and Huxleyiidae is a single, radially placed anterior
tooth and several short posterior teeth. In most known ancient
members of the order , the genus Afghanodesma ( Desparmet et al . , 1971 ) ,
the hinge is intermediate between the phaseoloid and the nucinelloid.
The anterior branch of the hinge margin in members of this genus bear
several teeth placed approximately as in Phaseolus , but the latter
genus is provided with small teeth like in Manzanella and they are
arranged practically in the same manner. In members of the suborder
Solemyina the hinge is entirely toothless. The digging life style of the
members of this order leads to unique forms of ani somyarinan and mono-
myarian conditions in which the primary development involves the anterior
adductor muscle. The changes noted in feeding lead to a strong devel-
opment of the cuticular cover and a decrease in the number of liver
ducts to two, each one of which in the Solemyidae open independently,
but in the Nucinellidae into a common atrium. The branchial lamellae
are directed dorsally and ventrally. A sufficiently distinctive adaptive
radiation was that of the superorder Septibranchia. The origin of this
was apparently the appearance of forms with byssal attachment . The use
of a quite incomplete septum as a water-moving mechanism which permitted

it to "feed on meiobenthic organisms in spite of its delicate weight. These
are the features it has in common with the contemporary Verticordiida
with the difference that within the limits of the order, there are forms
with byssal attachment (e_.g_. Verticordia ) as well as those without it
(e_.g_. Euciroa) ( Allen and Turner, 197M • One of the most ancient members
of the Bivalvia — Fordilla troyensis Barrande , is very close conchologically
as well as in regard to its muscle scars, to several contemporary
genera of the order Verticordiida (Starobogatov, 1977). This order,
which in spite of its primitiveness , is the origin of a peculiar
group of sedentary Septibranchia, the majority of which have almost
completely lost the mobile fold — namely the Order Conocardiida, whose
systematics and evolution have recently been worked out in detail
by Starobogatov (1977). The members of the 2 small contemporary
orders of Septibranchia — the Cuspidariida and Poromyida — are pred-
ators (inside their stomachs have been found harpacticoids , ostracods,
and mollusks ) , and their stomachs are sufficiently similar in their
manner of feeding. On the other hand, their septa are quite different
and cannot be derived one from the other, but only from the primitve
septa of the Verticordiida.

The appearance of the superorder Autobranchia brought about
the fundamental flourishing of the class Bivalvia with its numerous
genera and species. This possibly is bound up with the fact that
the branchial filtering apparatus with a ciliate water-moving
mechanism proved to be very favorable for the varied ways of life

(sedentary, mobile, drilling, burrowing) and for the varied ways of
feeding (filtration, collecting from the substrate surface, etc.).
Apparently the order Unionida ( = Actinodontida) was the origin of
almost all the Autobranchia orders, insofar as the original type of
the Autobranchia is considered to be unionoid since it preserves the
largest number of features similar to the Protobranchia stomach
( Neves skaya et al_. , 1971). From it are derived independently all
the other types of stomach of the members of the order (in addition
to the most advanced, the veneroid) . It is not possible to derive
one of these types from the other. For instance, when comparing the
mytiloid and the pectinoid (Purchon, 1957; Dinamani , 1967; Nevesskaya
et_ al . , 1971) it is easy to see that the second can by no means be
derived from the first with its tongue-shaped loop of the major
typhosole and its apertures placed alongside the diverticula of the
liver. This forces one to reject the generally accepted opinion
regarding the derivation of the order Pectinida from the Pterioidea.
In the stomach of Lyons i a californica Conrad (Narchi, 1968) it is
easy to perceive the last signs of the rudiments of the common liver
ducts; these common ducts of all the Autobranchia are characteristic
only for the forms with a unioid stomach type. Without discussing
in more detail the evolution of the stomach of the Autobranchia
since it was investigated earlier (Nevesskaya et_ al_. , 1971), we
note that the veneroid type is derived quite easily from the carditoid.
The left gastric caecum is formed near the terminal spirals of the
large typhlosoles, drawing it into itself, and the right caecum

(or two in the suborder Chamina) is formed on the middle path of the
major typhlosole near the zone of the greater concentration of the
liver duct openings. It is also not possible to derive the veneroid
stomach from the astartoid, since the origin of the formation of the
caeca and the spiral of the major typhlosole and its location would
then remain incomprehensible. The opposite pathway- proceeding from
the veneroid to the astartoid stomach by means of neotenic changes-
is likewise impossible. This forces us to reject the common supposition
(Purchon, I960 ) of a similar idea as well as the concrete hypothesis
such as the Turtoniidae being derived from the Veneridae (Ockelman, 196U).

The following basic tendencies in the evolution of the Auto-
branchia stomach may be noted: l) the disintegration of the common
liver ducts, and 2) the isolation of the crystalline style sac. We
have already referred to the first tendency above ; it is characteristic
that because of this, each diverticulum opens into the stomach by
an independent aperture, so that, in general, the number of diver-
ticula cannot immediately be told. Precisely for this reason it is
advisable to reject categorically the supposition that the Septibranchia
are very close to the Protobranchia (Purchon, 1956, 1963) — in both
cases the number of apertures is not large, 2 or 3, but the number of
diverticula is very different — as well as the supposition that the
Verticordiidae and the Lyohsiidae are interrelated (Allen and Turner, 197M
The isolation of the crystalline style sac , together with its intensified
function, arises independently in many orders of Autobranchia.

A sufficiently clear picture can also be seen in the evolution
of the hinge (Fig. 1). The most primitive hinge within the limits of
the Autobranchia is the lyrodesmoid hinge with uniform, undifferentiated
teeth, each one consisting of a primary plate. The differentiation of
the teeth into 2 marginal groups leads to the schizodont hinge, and
the differentiation into 3 groups (one postumbonal and 2 marginal) to
the actinodont hinge. It is curious to note that in the schizodont
hinge, the innermost teeth are located in the left valve, but in the
actinodont (and apparently also in the lyrodesmoid) they are in the
right valve. The most primitive actinodont hinge is present in the
genus Actinodonta — here the differentiation of teeth is still
extremely weak. The connection of the pterineoid hinge to the
actinodont is quite obvious and it has often been discussed in the
literature. Such widely known data can be used to derive the cyr-
todont hinge from the pterineoid and the arcoid (taxodont) from the
cyrtodont . No less obvious is the derivation of the isodont hinge
of the members of the order Pectinida from the schizodont hinge of the
Unionida, although this circumstance is usually ignored in the phy-
logenetic schemes, the pectinoid forms are derived from a form of the
Pterinea-Pteria type. It is obvious that the evolution of the shell
in the orders Mytilida ( = Cyrtodontida) and Pectinida proceeds in a

1. The location of the innermost teeth in Spondylus and Plicatula
in the right valve can by no means be viewed as secondary teeth in
these genera (Yonge, 1973). It is simply that the primary plate II
here is buried by the surrounding fibrous ligament layer.

remarkably parallel manner.

A greatly more complicated matter is found in the heterodont
groups, among which, by tradition (but without basis) the Pholadomyida
are also included. The derivation of the heterodont hinge from any
sort of (or sorts of) preheterodont hinge obviously raises immediate
doubts. However, the complication rests in the fact that the
heterodont hinges may come from various preheterodont forms and by
various paths (Nevesskaya et_ al_. , 1971). This is easily illustrated
specifically in the fact that the cyrtodont hinge may properly be
regarded as heterodont — the subumbonal teeth may properly be called
cardinal teeth, and the posterior, the posterior lateral teeth, all
the more so since the posterior teeth in both cases correspond only to
the primary plates which lie some distance from the umbonal section.

The hinges of members of the order Lucinida (= Astartida),
Carditida, and Venerida, in all likelihood, derive from the schizodont
hinge. In favor of their connection to the schizodont hinge can
firstly be cited the formation of the inner teeth from a number of
cardinal teeth, and the anterior lateral teeth from the single
primary plate; there is also the obvious absence (in the majority
of cases) of such inner cardinal teeth which are not related onto-
genetically to the corresponding lateral teeth. This means that in
the original hinge all the teeth were located along the anterior and
posterior portions of the hinge margin, and the subumbonal teeth
(as in the actinodont hinge) did not exist. In the second place in

10

several members of the order Astartida ( sic ) (suborder Erycinina), a
return to the primary plate was observed, which is located precisely
like the teeth of the schizodont hinge. These two points appear
sufficiently weighty to us to derive the numerous heterodont hinges
from the schizodont.

Here, however, there is a very serious difficulty. In all
heterodont hinges (except in the case of a reduction of teeth) the
innermost primary plates are located in the right valve, but in the
schizodont the innermost teeth are in the left valve. Here two
assumptions are possible: 1) the primitive plate I has been wrongly
designated and actually is no such thing (e_.g_. on account of the re-
duction of the innermost plates on the left valve), and 2) the teeth
of the heterodont hinge are transposed in comparison with the schizodont
teeth.

It appears to us that these assumptions do not exclude each other,
and it is possible to combine them in the interpretation of the hinges
of the members of several orders.

The lucinoid and astartoid hinges of the Lucinida rarely possess
lateral teeth AI or PI (Chavan, 1969, Treatise N2). In cases when
they are so designated, it is not sufficient to demonstrate that they
correspond to primary plate I, and primary plates II are the lateral
teeth of the left valve which lie outside them (Bernard, 1895)
(Nevesskaya, 1965) To a large degree, they are related to the teeth
of the pseudocyrenoid hin^e of the suborder Erycinina, where the

11

development of the teeth is practically unnoticeable. On the other
hand the single inner cardinal tooth of the left valve is always
designated 2; it fully corresponds to the tooth of the left valve of
the schizodont hinge.

The hinge of the order Carditida apparently is more properly
considered as transposed, and an analogy should be perceived between
the strong inner cardinal tooth of the right valve of. the schizodont
hinge (Fig. 2). In support of this view can be cited, among other
facts, the remarkable morphological and topographical similarity in
the lower forms. Here we must cite the improper designation of the
tooth here designated as 3a, since it cannot be related to the same
pair of primary plates, but only to the succeeding pair. When we
adhere to the connection between even and odd plates from the right
and left valves, then tooth 3b should be designated 1, and tooth 2
and UB perceived respectively as 2a and 2B. It is interesting to note
that the hinge of the unique representatives of the Carditida, the
Mecynodontidae (Haffer, 1959), and Arcticoidea, which is
close to it, is interpreted in precisely this way. If indeed, with
transposition there is a change in assigning the even and odd numbers
to the valves, then teeth 2 and Ua will be on the right valve, and
3a and 3b on the left .

The lucinoid, arcticoid, corbiculoid, and mactroid hinges of the
order Venerida should without doubt be looked upon as transpositions
(Fig. 2), since here it has been clearly shown that the innermost primary

12

plate lies in the right valve (Bernard, 1895; 1897; Munier-Chalmas , 1895;
Nevesskaya, 19-65; Le Pennec, 1973). But then the Venerida hinge can jus-
tifiably be compared to the Carditida hinge and one can even derive the
forms of the Septibranchia from them phylogenetically . In view of this
difference, things will be just as they are in the complete Carditida
hinges — the inner cardinal tooth of the right valve (that is 3b as it
is commonly designated) will develop, and in the hinges of the lower
Venerida, tooth- 1 is absent and develops only later in the higher
members of the order (Casey, 1952). This forces us to seek the ancestors
of the Venerida among those Carditida in which the inner cardinal tooth
of the right valve is underdeveloped or undeveloped. One must emphasize
the fact that deriving the Venerida hinge from the Carditida hinge is
in agreement with the data regarding the structure of the stomachs .

Of course, this supposition is only an hypothesis which requires
careful verification, and above all a study of the ontogenesis of the
hinges in the lower Carditida, and in those Lucinida with lateral tooth I,
In regard to the available information on the ontogenesis of the hinges
of the Venerida, all the data concerning the correspondence of teeth
to the primary plates remain unchanged; at this time we can add nothing
further to support or oppose this hypothesis.

1. In proposing this hypothesis we discuss only the correspondence
of teeth in various groups; we by no means are proposing a change in
their designations.

13

Attempts to compare the teeth of the pachyodont hinge of the
Hippuritida and other similar heterodont hinges were undertaken by
Douville (1918, 1935)- However, in hoth instances the author was
forced to accept the fact that all the teeth correspond to their
primary plates. This means that up to the present it has not been
shown that the pachyodont hinge is related to the heterodont. Ohdner
(1919) who studied the hinge development of Pseudochama and Arcinella
offered 3 possible interpretations. It is characteristic that the
number of "cardinal" teeth in the formation of the Arcinella
hinge is somewhat larger than in other hinges. This allows one to
presuppose a derivation which differs from the other heterodont hinges
of the members of the Hippuritida, and possibly the origin here was
not the schizodont, but the actinodont hinge. The desmodont condition,
strictly speaking, is generally without teeth, and thus the supposition
of its heterodont character is not at all supported. However, in the
genus Alula , usually placed in Grammysiidae and in members of the
Pandoridae there are tooth-like plates which in the pandorids fill
the role of a crux for the retention of the internal ligament. By
analogy with the lithodesmal support of the order Pectinida one may
suppose that they were formed from the hinge teeth, and then we must
derive the desmodont hinge directly from the lyrodesmodoid.

The evolution of the basic adaptive types of Autobranchia as a
whole is presented in the Table proposed by Douville (1912, 1913),
with the sole rectification that the transition among these types
comes about repeatedly and independently in various groups (Fig. 3).

1U

In this table, it is seen that the evolution of the adaptive features
of the Autobranchia in its first stage brought about considerable
varied forms commensurate with adapting to the various manners of
a sedentary life style. It is typical that in this way the basic
processes of divergence proceeded from superorder to order. The
second high point of evolutionary variation took place in the basic
swimming life style, and the transition from it to the burrowing and
then back again to the sedentary. The transition to the burrowing
life style in the early stages played a minor role. The free swimming
life style to a considerable degree limits the shapes of the shells,
whereas a sedentary life style leads to a remarkable large number
of variations. This circumstance, together with the earlier div-
ergence of sedentary forms , also explains the tendency to the assim-
ilation of Lucinida, Carditida, and Venerida into one order and the
division of the Unionida into 3 independent orders and the Mytilida
into h, as is seen in most contemporary systems. Phylogenetically ,
these considerations may be illustrated by a table of the evolution
of the bivalve orders, which is a further development of the table
presented by Nevesskaya et al. (1971) with several clarifications
published by Scarlato and Starobogatov (1975). An analysis of the
evolutionary path taken by the various bivalve groups allows one
to offer a table of the phylogenetic relationships of the super-
families of each order (Figs. 5-9).

In concluding this article we offer a classification system of
the Bivalvia down to the family level. This system also presents

15

the results of further studies of the system proposed by Nevesskaya
et al . (1971). However, it does not propose nomenclatural changes
relating to the priority principle (this appears clearly stated
in the synonymies of the superorders , orders, and suborder — we
have even standardized the spelling of the final endings of the
synonyms) [in the classification, synonyms are placed in parentheses]
A few changes in the content of the superfamilies and families are
explained in the notes; the references to the notes appear [in
brackets] after each corresponding superfamily. After each family
we briefly indicate by letters their distribution in time, employing
the following abbreviations: Cm-Cambrian, 0-Ordovician , S-Silurian,
D-Devonian, C-Carboniferous , P-Permian, T-Triassic , J-Jurassic,
Cr - Cretaceous , Pg-Paleogene , Ng-Neogene, R-Recent .

16

Class BIVALVIA LIME, 1758

Super-order. PROTOBRANCHIA Pelseneer, 1889 ( = Nuculoida Dall, 1889)

Order. Nuculida Dall, 1889
Suborder. Radiidentina Scarlato et Starobogatov, 1975

Superfamily. Phaseoloidea Scarlato et Starobogatov, 1971 C1H Phaseolidae
Scarlato et Starobogatov, 1971-R, Lametilidae Allen et Sanders,
1973-R.

Superfamily. Radiidentoidea Egorova et Starobogatov, 1975: Radiidentidae
Egorova et Starobogatov, 1975-R-

Suborder. Nuculina Dall, 1889 ( = Ctenodontina Douville, 1912)

Superfamily. Ctenodontidea Wohrmann, 1893 C2H: Praenuculidae McAlester,

1969-O-D, Ctenodontidae Wohrmann, 1893-O-C, Tindariidae Verrill

et Bush, 1897-Ng-R, (?) Isoarcidae Keen, 1969-J-Cr.
Superfamily. Malettioidea H. Adams et A. Adams, 1858 C3H : Malettiidae H.

Adams et A. Adams, 1858-O-R, Cadomiidae fam. nov.-O-S, Pseudarcidae

fam. nov.-O-D.
Superfamily. Nuculoidea Gray, 182U : Nuculidae Gray, 182U-O-R.
Superfamily. Sareptoidea A. Adams, i860 ihl : Pristiglomidae Sanders et Allen,

1973-R, Sareptidae A. Adams, 1860-R, Zealedidae fam. nov.-Pg-R.
Superfamily. Nuculanoidea H. Adams et A. Adams, 1858 C5H; Nuculanidae

H. Adams and A. Adams ,1858-D-R, Adranidae fam. nov.-R, (?) Poro-

ledidae fam. nov.-Pg-R.

17

Order. Solemyida Newell, 1965
Suborder. Nucinellina Scarlato et Starobogatov, 1971

Superfamily. Afghanodesmatoidea superf. nov. C6]: Afghanodesmatidae fam.

nov.-O.
Superfamily. Manzanelloidea Chronic, 1952: Manzanellidae Chronic, 1952-P,

Nucinellidae Vokes, 1956-J-R.
Superfamily. Huxleyioidea Scarlato et Starobogatov, 1971: Huxleyiidae

Scarlato et Starobogatov, 1971-R.

Suborder. Solemyina Newell, 1965 ( = Solenomyina Dall, 1889)

Superfamily. Acharacoidea superf. nov. LT1: Acharacidae fam. nov.-D-R.
Superfamily. Solemyoidea H. Adams et A. Adams, 1857: Solemyidae H. Adams
et A. Adams, 1857-D-R.

Superorder. Autobranchia Grobben, 189^+ ( =Mytiloida Ferussac, 1822)

Order. Unionida Stoliczka, 1871
Suborder. Lyrodesmatina Scarlato et Starobogatov, 1971

Superfamily. Lyrodesmatoidea Ulrich, 189^ : Lyrodesmatidae Ulrich, 189^-0.
Superfamily. Palaeanodontoidea Mo dell, 1964 C8H: Palaeanodontidae Modell,
196U-P-T, Sinomyidae fam. nov. -P.

Suborder. Unionina Stoliczka, 1871 ( =Trigoniina Dall, 1889)

18

Superfamily. Lamellidentoidea Vogel, 1962 C93: Lamellidentidae Vogel ,
1962-Cm.

Superfamily. Carydioidea Haf f er , 1959 C9H: Carydiidae Haffer, 1959-D.

Superfamily. Trigonodoidea Modell, 19^2 C10H : Trigonodidae Modell,
19i+2-P-J, Desertellidae Dechaseaux, 19^6-Cr.

Superfamily. Trigonioidea Lamarck, 1819 : Miophoriidae , Bronn, I8U9-D-J,

Trigoniidae Lamarck, 1819-T-R, Scaphellinidae Newell et Ciriacks, 1962-P.

Superfamily. Unionoidea Rafinesque, 1820: Trigonioididae Cox,

1952-J-Cr, Pseudohyriidae Kobayashi , 1968-Cr, Sainschaniidae
Kolesnikov, 1977-Cr, Margaritiferidae Henderson, 1929-J-R,
Amblemidae Rafinesque, 1820-J-R, Unionidae Rafinesque, 1820-J-R,
Lampsilidae Ihering, 1901-T-R, Hyriidae Swainson, l8*iO-T-R.

Superfamily. Mullerioidea Deshayes, 1830: Mycetopodidae Modell, 19^2-T-R,
Mulleriidae Deshayes, 1830-R.

Superfamily. Etherioidea Deshayes, 183O: Mutellidae Gray I8U7-T-R,

Etheriidae Deshayes, 1830-R, Pseudomulleriidae Starobogatov, 1970-R.

Suborder. Actinodontina Douville, 1912 ( =Modiomorphina Newell, 1969)

Superfamily. Actinodontoidea superf. nov. till: Actinodontidae fam. nov.-O.
Superfamily. Cycloconchoidea Ulrich, 188U [123: Cycloconchidae Ulrich,

188U-0, Babinkidae Horny, 1960-0, Allodesmatidae Dall, 1895-0- S.

Saffordiidae fam. nov.-O, Ischyrodontidae fam. nov.-O.

19

Superfamily. Actinodontophoroidea Newell, 1969 C133 : Tanaodontidae fam.

nov.-D, Actinodontophoridae Newell, 1969-P-T.
Superfamily, Nyassoidea Hall, 1885 ClU]: (?) Nyassidae Hall, 1885-D. (?)

Archanodontidae Weir 1969-D-C, Anthracosiidae Amalitzki, 1892-C-T ,

Carbonicolidae Cox, 1932-C-P, Utschamiellidae Kolesnikov, 197T-T-J.
Superfamily. Modiomorphoidea Miller, 1877 C153: Coxiconchidae Babin, 1977-0

Modiolopsidae Fis.cher, 1887-0-D, Modiomorphidae Miller, 1877-O-P,

(?) Kr'nerkaellidae Betekhtina, 1972-P, (?) Abiellidae Starobogatov,'

1970-P, (?) Prilukiellidae Starobogatov, 1970-P.
Super family. Gastrochaenoidea Gray, 18U0 Cl6D: Hippomyidae fam. nov.-O,

Gastrochaenidae Gray, I8U0-J-R.

Order. Mytilida Ferussac, 1822
Suborder. Bteriina Newell, 1965 ( =Praecardiina Newell, 1965)

Superfamily. Praecardioidea Hoernes, 1886 C17D: Palaeocardiidae fam.

nov.-0-S, Praecardiidae Hoernes, 1886-S-D, Necklaniidae fam. nov-

S, Cardiolidae Fischer, 1886-S-C.
Superfamily. Ant ipleuro idea Neumayr, 1891 LIU : Dexiobiidae Newell et

LaRocque, 1969-S-C, Antipleuridae Neumayr, 1891-O-D.
Superfamily. Lunulicardioidea Fischer, 1886 C173: Lunulicardiidae Fischer,

1886-S-C. Vlastidae Neumayr, 1891-O-D.
Superfamily. Ambonychioidea Miller, 1877 Cl8D: Ambonychiidae Miller,

I877-O-C, Myalinidae Freeh, 1891-D-J, Naiaditidae fam. nov.-C-T,

20

Eurydesmatidae Reed, 1932-P, Monopteriidae Newell, 1969-C-P,

Procopievskiidae Vokes, 1967-P.
Superfamily. Pterioidea Gray, I8U7 C19H: Ahtioconchidae Eberzin, 1960-0

Pterineidae Miller, 187T-0-P, Actinodesmatidae fam. nov-D, Pterii-

dae, Gray, I8U7-T-R, (?) Kochiidae Maillieux, 1931 -D.
Superfamily. Pinnioidea Leach, 1819: Pinnidae Leach, 1819-C-R.
Superfamily. Mysidelloidea Cox, 196U L201: Mysidellidae Cox, 196U-T,

Pergamidiidae Cox, 1969-T.
Superfamily. Posidonioidea Freeh, 1909 C213 : Posidoniidae Freeh, 1909-C-J,

Halobiidae Kittl, 1912-T-Cr, Pterinopectinidae Newell, 1938-S-P,

Deltopectinidae Dickins, 1957-P, Oxytomidae Ichikawa, 1958-P-Cr.
Superfamily. Aviculopectinoidea Meek et Hayden, l86h : Aviculopectinidae

Meek et Hayden, 1861+-C-J, Streblochondriidae Newell, 1938-C-T,

Pseudomonotidae Newell, 1938-C-P, (?) Chaenocardiidae Miller, 1889-

C-P, Monotidae Fischer, 1887-T.
Superfamily. Euchondrioidea Newell, 1938 C223: Euchondriidae Newell, 1938-P,

Crenopectinidae fam. nov.-D.
Superfamily. Bakevellioidea King, 1850: Bakevelliidae King, 1850-P-Pg,

Cassianellidae Ichikawa, 1958-P-T, Isognomonidae Woodring, 1925-P-R,

Dattidae Healey, 1908-T.
Superfamily. Inoceramoidea Giehel, 1852: Inoceramidae Giehel, l852-P-Pg.
Superfamily. Malleoidea Lamarck, 1819: Pulvinitidae Stephenson, 19^1-J-R,

Malleidae Lamarck, l8l9-J-R.
Superfamily. Buchioidea Cox, 1953: Buchiidae Cox, 1953-T-Cr.

21

Suborder. Cyrtodontina Scarlato et Starobogatov, 1971

Superfamily. Cyrtodontoidea Ulrich, 189^ C233: Cyrtodontidae Ulrich, 189U-

0-D, Matheriidae fam. nov.-O-S.
Superfamily. Limarcoidea superf. nov. L2kl: Limarcidae fam. nov,-Pg-R.

Suborder. Mytileina Ferussac, 1822 ( = Ostreina Ferussac, 1822

=Arcina Stoliczka, 1871)

Superfamily. Limopsoidea Dall, 1895 C25H: Philobryidae Bernard, l897-Pg-R,

Limopsidae Dall, 1895-J-R, Pichleriidae fam. nov-T, Aupouriidae fam.

nov . -Ng-R .
Superfamily. Mytiloidea Rafinesque, l8l5: Mytilidae Rafinesque, 1815-D-R.
Superfamily. Glycimeridoidea Newton, 1922 Z26l: Glycimerididae Newton,

1922-Cr-R, Melaxineidae Habe, 1977-Cr-R.
Superfamily. Arcoidea Lamarck, 1809: Parallelodontidae Dall, 1898-O-R,

Cucullaeidae Stewart, 1903-J-R, Arcidae Lamarck, 1809-T-R, Noetiidae

Stewart, 1930-Cr-R.
Superfamily. Gryphaeoidea Vialov, 1936: Gryphaeidae Vialov, 1936-T-R,

Exogyridae Vialov, 1936-J-Ng.

1. We utilize this spelling to distinguish this subordinal name from the
generic spelling Mytilina .

22

Superf amily . Ostreoidea Rafinesque, 1815 ^2J1 : Crassostreidae fam.
nov-Cr-R, Ostreidae Rafinesque, 1815-T-R.

Order. Pectinida H. Adams et A. Adams, 1857
Suborder. Pectinina H. Adams et A. Adams, 1857

Superfamily. Leiopectinoidea Krasilova, 1959 C28D: Rhombopteriidae

Korobkov, 1960-0-S, Leiopectinidae Krasilova, 1959-O-D.
Superfamily. Plicatuloidea Watson, 1930 C29H: Plicatulidae Watson, 1930-T-R,
Superfamily. Spondyloidea Gray, 1826 C293: Spondylidae Gray, 1826-J-R.
Superfamily. Pernopectinoidea Newell, 1938 C30H: Pernopectinidae Newell,

1938-C-P, Entoliidae Korobkov, 1960-T-Cr, Propeamussiidae Abbott,

195U-J-R.
Superfamily. Pectinoidea Rafinesque, 1815 : Pectinidae Rafinesque, 1815-T-R.
Superfamily. Limarioidea Rafinesque, 1815, C313: Limariidae Rafinesque,

1815-C-R, Terquemiidae Cox, 196U-P-Cr, (?) Chondrodontidae Freneix,

1959-Cr, Dianchoridae Sobetski, 19TT-Cr.

Suborder. Anomiina Dall, 1889 ( =Dimyina Pelseneer, 1906)

Superfamily. Dimyoidea Fischer, 1886 : Dimidae Fischer 1886-J-R.
Superfamily. Heteranomioidea superf. nov. E32H: Atretidae fam. nov.-T-Cr,

Heteranomiidae fam. nov.-R.
Superfamily. Anomioidea Rafinesque, 1815 C32H: Placunidae Gray, l8U0-Cr-R,

Anomiidae Rafinesque, 1815-P-R.

23

Order. Pholadomyida Newell, 196 5
Suborder. Laterrrulina Scarlato et Starobogatov, 1978 ( = Anatinina Dall, 1889)

Superfamily. Grammysioidea Miller, 1877 C333: Grammysiidae Miller, 1877-

0-P, Promacridae fam. nov.-O-C.
Superfamily. Orthonotoidea Miller, 1877 C33H: Sanguinolitidae Miller, 1877-

S-P, Orthonotidae Miller, 1877-O-D.
Superfamily. Cercomyoidea Crickmay, 1936 C33H: Protomyidae fam. nov.-D-P,

Cercomyidae Crickmay, 1936-D-Cr.
Superfamily. Myochamoidea Bronn, 1862 C323: Periplomatidae Dall, 1895-

Cr-R, Laternulidae Hedley, 1918-J-R, Lyonsiidae Fischer, l877-Pg-R,

Margaritariidae Vokes, 196U-Ng, Myochamidae Bronn, l862-Ng-R.
Superfamily. Pandoroidea Rafinesque, 1815 C3^H: Pandoridae Rafinesque,

1815-Pg-R, Cleidothaeridae Hedley, 19l8-Ng-R,
Superfamily. Thracioidea Stoliczka, 1870 [3^3: Thraciidae Stoliczka,

18T0-J-R.

Suborder. Pholadomyina Newell, 1965

Superfamily. Edmondioidea King, 1850 C353: Edmondiidae King, 1850-D-P,
Megadesmatidae Vokes, 1967-C-P, Myoniidae fam. nov.-C-P.

Superfamily. Pholadomyoidea Gray, I8U7 C351: Pholadellidae Miller,
1877- D-C, Pholadomyidae Gray, 181+7-C-R.

Superfamily. Pleuromyoidea Zittel, l88l C353: Pleuromyidae Zittel, l88l-T-Cr.

2k

Ceratomyidae Arkell , 193 1 +-T-Ng, Myopholadidae Cox, 196U-J-O,
Burmesiidae Healey, 1908-T-J.

Suborder. Clavagellina Newell, 1965

Super family. Clavagelloidea Orbigny, I8U3: Clavagellidae Orbigny, 18^3-Cr-R,
Superfamily. Penicilloidea Scarlato et Starobogatov, 1971 C36H:

Penicillidae Scarlato et Starobogatov, 1971-Pg-R, Humphreyidae

fam. nov.-R.

Order. Hippuriti da Newell, 19&5

Superfamily. Megalodontoidea Morris et Lycett, 1853 C373: Plethocardiidae
fam. nov.-O-P, Tusayanidae fam. nov.-D, Megalodontidae Morris et
Lycett, 1853-S-T, Pachyrismatidae fam. nov.-D.(?) Ferrasiidae fam.
nov.-P. (?) Pterocardiidae fam. nov.-J-Cr.

Superfamily. Caprotinoidea Gray, 18U8 C38D: Diceratidae Dall , 1895-J,

Monopleuridae Munier-Chalmas , l873-Cr-Pg, Caprotinidae Gray, 18U8-
Cr, Caprinidae Orbigny, l850-Cr, (?) Lithiotidae Reis, 1903-J.

Superfamily. Requienioidea Douville , 191^ C38H: Epidiceratidae Rengarten,
1950-J-Cr, Requieniidae Douville, 191^-J-Cr.

Superfamily. Hippuritoidea Gray, 18U8 : (?) Plicatostylidae Lupher et
Packard, 1930-J, Hippuritidae Gray, l8U8-Cr, Radiolitidae Gray,
l8U8-Cr.

25

Superfamily. Arcinelloidea Scarlato et Starobogatov, 1971: Arcinellidae
Scarlato et Starobogatov, 1971-Pg-R.

Order. Lucinida Stoliczka, 1871
Suborder. Astartina Scarlato et Starobogatov, 1971

Superfamily. Astartoidea Orbigny, 18UU C39H : Astartidae Orbigny, 18UU-0-R,
Cardiniidae Zittel, 1881-O-R, Opidae Chavan, 1952-D-Cr, Myophori-
cardiidae Chavan, 1969-T.

Superfamily. Crassatelloidea Ferussac, 1822: Crassatellidae Ferussac,
1822-D-R.

Superfamily. Mactromyoidea Cox, 1929 CUOD : Mactromyidae Cox, 1929-D-R,
Montanariidae fam. nov.-D, Fimbriidae Nicol, 1950-C-R.

Superfamily. Hiatelloidea Gray, 182H : Hiatellidae Gray, 182U-P-R, Hippo-
podidae Cox, 1969-J.

Superfamily. Pseudocardinioidea Martinson, 196l: Pseudocardiniidae Martin-
son, 1961-J, Ferganoconchidae Martinson, 1961-J, Kijidae Kolesnikov,

1977-J.
Superfamily. Cycladoidea Rafinesque, 1820 CUlD; Neomiodontidae Casey,

1955-J-Cr, Cycladidae Rafinesque, 1820-J-R, Pisidiidae Gray, 1857,
-Ng-R, Euperidae Heard, 1965-Pg-R.

26

Suborder. Lucinina Stoliczka, 1871 C*+2D
Illioniidae fam. nov.-S-D, Thyasiridae Dall, 1901-T-R, Lucinidae Fleming,

1928-J-R.

Suborder. Erycinina Fischer, 1887 ( = Leptonina Dall, 1889)

Superfamily. Donacoidea Fleming, 1828 Zk3^: Sowerbyidae Cox, 1929-T-J,

Tancrediidae Meek, l86U-T-Cr, (?) Hemidonacidae Iredale et McMic-

hael, 1962-R, Donacidae Fleming, l828-Cr-R.
Superfamily. Cyamoidea Philippi, I8U5 CUU H : Cyamidae Philippi l8U5-Ng-R,

Perrierinidae Soot-Ryen, 1959-J-R. Turtoniidae Clark, l855-Ng-R,

Sportellidae Dall, 1899-J-R, Neoleptonidae Thiele, 193^-Ng-R.
Superfamily. Kellioidea Forbes et Hanley, 18U8 : Erycinidae Deshayes, 1850-

Pg-R, Kelliidae Forbes et Hanley, l8U8-Pg-R.
Superfamily. Leptonoidea Gray, 18^7: Leptonidae Gray, 18^7-Cr-R, Mon-

tacutidae Clark, l855-Pg-R.
Superfamily. Cyrenoidoidea H. Adams et A. Adams, 1857 Zh^l: Cyrenoididae

H. Adams et A. Adams, 1857-R.
Superfamily. Gal eommato idea Gray, I8U0 Lh6l : Galeommatidae Gray, 18^0-

Cr-R, Cyamionematidae fam. nov.-Pg-R, Ephippiodontidae fam. nov.-R,

Vasconiellidae fam. nov.-R.

Suborder. Chlamydoconchina Scarlato et Starobogatov, 1975
Chlamydoconchidae Dall, 1899-R

27

Order. Carditida Dall , 1889

Superfamily . Carditoidea Fleming, 1828 Lh^l : Archaeocardiidae Khalfin,
19^-0-S-D, Terraiidae fam. nov.-P-T, Carditameridae Chavan, 19&9-
D-R , Aenigmoconchidae Betekhtina, 1968-P, Carditidae Fleming, 1828-
Pg-R, Miodomerididae Chavan, 1969-Pg-R, Thecaliidae Dall, 1903-R.

Superfamily. Kalenteroidea Marwick, 1953 C^8]: (?) Redoniidae Babin, 1966-
0. (?) Butovicellidae Kriz, 1965-S, Mecynodontidae Haffer, 1959-D.
Kalenteridae Marwick, 1953-P-J, Permophoridae van der Poel , 1959-
D-T, Myoconchidae Newell, 1957-D-Cr.

Superfamily. Condylocardioidea Bernard, 1897 CU9H ; Cunidae Chavan, 1969-
Pg-R, Condylocardiidae Bernard, l89T-Pg-R.

Order. Venerida H. Adams et A. Adams, 1856
Suborder. Tellinina Stoliczka, 1871 ( =Cardiina Fischer, 1887
= Tridacnina Dall, 1889)

Superfamily. Tridacnoidea Lamarck, 1819 C50H: Septocardiidae Kafanov
et Starobogatov, 1977-T, Goniocardiidae fam. nov.-Pg, Avicu-
lariidae fam. nov.-Pg, Tridacnidae Lamarck, l8l9-Cr-R.

Superfamily. Cardioidea Lamarck, 1809 C513: Protocardiidae Keen, 1951-
T-R , Cardiidae Lamarck, l809-Cr-R, Clinocardiidae Kafanov,
1975-Ng-R , Lymnocardiidae Stoliczka, l870-Ng-R, Fragidae Steward,
1930-Pg-R.

28

Superfamily. Ungulinoidea H. Adams et A. Adams, 1857: Ungulinidae
H. Adams et A. Adams, l85T-Cr-R.

Superfamily. Tellinoidea Blainville, l8lU: Unicardiopsidae Vokes, 1969-J,
Quenstedtiidae Cox, 1929-J, Tellinidae Blainville, l8lU-Cr-R,
Psammobiidae Fleming, l828-Cr-R, Icanotidae Casey, 1961-Cr,
Solecurtidae Orbigny, l8U6-Pg-R, Pharellidae Tryon, l88U-Ng-R.

Superfamily. Scrobicularioidea H. Adams et A. Adams, I856: Scrobiculariidae
H. Adams et A. Adams, 1856-Pg-R, Semelidae Stoliczka, l8T0-Pg-R.

Suborder. Venerina H. Adams et A. Adams, 1856 ( =Isocardiina Dall, 1889)

Superfamily. Arcticoidea Newton, 1891: Arcticidae Newton, 1891, T-R,

Trapeziidae Lamy, 1920-Cr-R, Euloxidae Gardner, 19^3-Ng, Pollicidae
Stephenson, 1953-Cr, Bernardinidae Keen, 1969-R, Ptychomyidae Keen,
1969-Cr. (?) Lahiliidae Finlay et Marwick, 1937-Cr-Ng.

Superfamily. Kellielloidea Fischer, 1887: Kelliellidae Fischer, l887-Pg-R.

Superfamily. Gaimardioidea Hedley, 19l6: Gaimardiidae Hedley, 19l6-Ng-R.

Superfamily. Glossoidea Gray, I8H7 : Glossidae Gray, l8U7-Pg-R, Dicer-
ocardiidae Kutassy, 193^-T-Cr, Ceratomyopsidae Cox, 196I+-J.

Superfamily. Corbiculoidea Gray, l8Uj: Corbiculidae Gray, I8U7-J-R,
Limnocyrenidae Kolesnikov, 1977-J-Cr.

Superfamily. Veneroidea Rafinesque, 1815: Veneridae Rafinesque, l8l5-Cr-R,
Petricolidae Deshayes, l839-Pg-R, Cooperellidae Dall, 1900-Pg-R,
Glauconomidae Gray, 1853-R, Vesicomyidae Dall, 1908-Pg-R, Rzeha-
kiidae Korobkov, 195^— Ng.

29

Superfamily. Pleurodesmatoidea Cossmann et Peyrot , 1909 C52D : Aloididae
Thiele, 193^-J-R, Erodonidae Winckworth, 1932-Pg-R, Spheniopsidae
Gardner, 1928-Pg-R, Pleurodesmatidae Cossmann et Peyrot, 1909-Pg-Ng.

Suborder. Chamina Stoliczka, 1871:
Chamidae Lamarck, l809-Cr-R.
Suborder. Myina Stoliczka, 1871 ( = SDlenina Dall 1889

=Mactrina Dall, 1889)

Superfamily. Solenoidea Lamarck, 1809 : Cultellidae Davie s , 1935-Cr-R,

Solenidae Lamarck, 1809-Pg-R.
Superfamily. Dreissenoidea Gray, 18^0: Dreissenidae Gray, l8U0-Pg-R.
Superfamily. Mactroidea Lamarck, 1809: Mactridae Lamarck, 1809-Cr-R,

Tanysiphonidae Scarlato et Starobogatov, 1971-R* Anatinellidae Gray,

1853-R, Mesodesmatidae Gray, l839-Pg-R, Cardiliidae Fischer, 1887-

Pg-R.
Superfamily. Myoidea Lamarck, 1809: Myidae Lamarck, l809-Pg-R, Rae-

tomyidae Newton, 1919-Pg.

Suborder. Pholadina H. Adams et A. Adams, 1858:
Pholadidae Lamarck, 1809-J-R, Teredinidae Rafinesque, l8l5-Cr-R,

Superorder. Septibranchia Pelseneer, 1889
( = Conocardioida Neumayr, 1891)

30

Order. Verticordiida Scarlato et Starobogatov, 1971
( =Fordillida Pojeta, 1975)

Super family. Fordilloidea Pojeta, 1975: Fordillidae Pojeta, 1975-Cm.
Superfamily. Verticordioidea Stoliczka, 1870: Verticordiidae Stoliczka,

l8T0-Pg-R, Eucirioidae Dall, l89 1 +-R, Lyonsiellidae Scarlato et

Starobogatov, 1971-R.

Order. Conocardiida Neumayr, 1891
Suborder. Conocardiina Neumayr, 1891

Superfamily. Eopterioidea Miller, 1889: Stolidotidae Starobogatov, 1977-
Cm-S, Eopteriidae Miller, 1889-0, Pseudotechnophoridae Star-
obogatov, 1977-0.

Superfamily. Euchasmatoidea Starobogatov, 1977: Euchasmatidae Staro-
bogatov, 1977-Cm-D.

Superfamily. Conocardioidea Miller, 1889 : Bransoniidae Pojeta et Runnegar,
1976-0-T, Hippocardiidae Pojeta et Runnegar, 1976-0-C, Conocardiidae
Miller, 1889-D-P.

Suborder. Ribeiriina Kobayashi, 1933 ( =Ischyriniina
Pojeta et Runnegar, 1976)

Superfamily. Technophoridea Miller, 1889: Ozomiidae Starobogatov, 1977-0,
Ribeiriidae Kobayashi, 1933-Cm-O, Techophoridae Miller, l889-Cm-0.

31

Super family. Ischyrinioidea Kobayashi, 1933: Tolmachoviidae Staro-
bogatov, 19TT-0, Ischyriniidae Kobayashi, 1933-0.

Order. Cuspidariida Scarlato et Starobogatov, 1971:
Cuspidariidae Dall, l886-Cr-R.

Order. Poromyida Pelseneer, 1906:

Poromyidae Dall, l886-Cr-R, Cetoconchidae Ridewood, 1903-R.

32

Notes

1. The Phaseolidae and the Lametilidae differ from the Radiidentidae
( =Siliculidae Allen and Sanders, 1973) approximately in the way Nucu-
loidea differ from Nuculanoidea (Allen and Sanders, 1973), and this
compels us to regard them as separate superfamilies . In the family
Lametilidae we leave only the genus Lametila Allen and Sanders 1973
with long teeth, whereas Prolametila Allen and Sanders 1973 with

short teeth and perpendicular sections in the preumbonic teeth we
transfer to the Phaseolidae.

2. In the superfamily Ctenodontoidea we include all groups with
an external ligament and without a pallial sinus, among them
Praenuculidae despite their outward nuculoid appearance. We also
conditionally place here Isoarcidae.

3. The Malletiidae in the usual acceptance is not monogeneric.
Cadomia Tromelin 1877; Dysodonta Mansuy 1913, and possibly Ekstadia
Soot-Ryen 196h and S luha Barrande l88l should in our opinion be united
in new independent family Cadomiidae, characterized by the umbo
strongly shifted forward and a complete reduction of all primary

and radial components of the posterior teeth. Pseudarca Tromelin
and Lebesconte 1875 , Tropinuculites McLearn 1918 and Nuculites 18^1,
should be separated into the new independent family Pseudarcidae ,
characterized by the strongly lengthened, almost blade-like shell,

33

the development of numerous but very small teeth only in the posterior
branch of the hinge margin and the strong development of the septal
plate separating the posterior muscle scar.

h. In the Nuculanidae sensu lato there is a large group of
forms with the shell not extended posteriorly and lacking a sinus.
Sanders and Allen (1973), after having studied one of these forms —
Pristigloma Dall 1900 — placed it, together with Microgloma Sanders
and Allen 1973 into the separate family Pristiglomidae of the superfamily
Nuculacea. It seems to us that there is no basis for separating the
non-siphon bearing Nuculanidae s_.l_. although it is necessary to detach them
from the superfamily Nuculanoidea. This compels us to place these
groups into a special superfamily Sareptoidea, which includes, in
addition to Pristiglomidae and Sareptidae, also the newly recognized
Zealedidae (with the sole genus Zealeda Marwick 192U); they are
characterized by the presence of a long hinge, a posteriorly ex-
tended rostrum, and the presence of divaricate sculpture on the anterior
part of the valve.

5. We place Poroleda Tate 1893 and Propeleda Iredale 192U
(including Lamellildea Cotton 1930) in the new separate family
Poroledidae , characterized by the sharply projecting posterior half
of the shell and the almost longitudinally arranged, straight teeth
(possibly corresponding to the perpendicular elements of the nuculoid
hinge teeth). Adrana H. and A. Adams 1858 is separated into its
own new family Adranidae, characterized by its extremely lengthened

3U

shell (which preserves the central location of the umbo), and the
numerous , very small hinge teeth.

6. Afghanodesma Termier and Termier 1971, judging by its
characteristic anisomyarian condition and its hinge structure, is
related not to the Praenuculidae , as the authors stated when des-
cribing it (Desparmet et_ al_. , 1971), but is a more primitive member
of the suborder Nucinellina. It should be put into its own new
superfamily Afghanodesmatoidea and family Afghanodesmatidae , char-
acterized by its round shell with weakly, posteriorly placed umbo,
external ligament, a considerable stronger anterior than posterior
adductor muscle, the presence on the anterior part of the hinge plate
of several longer almost radially arranged teeth, and several short
perpendicular teeth on the posterior part.

7. Acharax Dall 1908 and Adulomya Kuroda 1931 should be placed
in the separate family Acharacidae and superfamily Acharacoidea,
characterized by the complete absence of an internal ligament and with
an external ligament strengthened by the nymphs .

8. The systematic s of the Carboniferous-Permian non-marine
mollusks are unbelievably complicated because the majority of forms
are known only from the outer shell. Thus there is a great variety
in the systems proposed (Weir, 1969, Treatise NI ; Starobogatov, 1970;
Betekhtina, 1972, 197*0. In all cases, however, the most difficult
and most disputed question is the one regarding the affinities of
the family, superfamily, and order. We basically follow the system

35

elaborated by Betekhtina (197*0 with several alterations regarding
the affinities of the orders and superfamilies . Specifically, the
Palaeanodotidae Modell 196*+ ( = Paleomutelidae Weir, 1969 — non
Weir in Vokes, 1967, nomem nudum ) is combined with the Lyrodes-
matoidea by the character of the hinge and should be separated into
a special super family of the same suborder. In the family Pala-
eanodontidae we place: Paleomutela Amalitzki 1892, Rectodontia
Tschernyschew 19*+3; Oligodontella Gussev 1963 ( = 01igodon Amalitzki
1892 non Boie 1826) , Tailugania Papin 1965, Palaeanodonta Amalitzki
1895, Neamnigenia Khalfin 1950, and Anthoconaia Trueman and Weir 19*+6.
Into this superfamily we provisionally place the Sinomyidae, new family,
including Sinomya Pogorevich 1977 and Pseudomodiolus Betekhtina,
1966, characterized as follows: shell irregularly quadrangular,
beaks stongly placed anteriorly (but not to the anterior tip) , the
prodissoconch of the shell type G (fide Betekhtina, 197*0, the
posterior margin hinge type III or IV6 — ( ibid . ) . It is characteristic
that the prodissoconch of type G is also found in the Anthracosiidae.

9. The superfamily Cycloconchoidea is usually considered to
be unbelievably heterogeneous because its members are placed in various

1. Type-species P_. ellipticus Betekhtina, 1966 here designated by
Betekhtina. On p. 25 and 96 Betekhtina (197*0 named the prodis-
soconch shell of Pseudomodiolus type G, but on p. 1H3 she called
it type B.

36

suborders on account of the hinge structures. The Lamellidentidae
and Carydiidae possess a schizodont hinge and should therefore he
included in the suborder Unionina. For this reason they should be
placed in different superfamilies , since they have remarkable differ-
ences in the hinge structure. The other families usually placed here
should be included in the suborder Actinodontina.

10. We place the Desertellidae in the superfamily Trigonodoidea
and not in the Unionoidea (as is customarily done) because of the
considerable similarity of the hinges of Desertella and Trigonorlus .

11. Actinodonta Phillips 18U8 should be set aside into a new in-
dependent family and superfamily in view of its primitive hinge: the
subumbonal teeth are not yet sharply separated from the anterior and
posterior teeth in contrast to Cycloconcha where this separation is
very sharp.

12. In the superfamily Cycloconchoidea we include those forms
with a sharply differentiated premarginal teeth and subumbonal teeth.
In addition to the Cycloconchidae (with Cycloconcha Miller I87M

and the Allodesmatidae (with Allodesma Ulrich 189^, Glyptarca
Hicks 1873, and Anodontopsis McCoy 1851) we place here the Babinkidae
in which, judging by the data of Babin (1977), the hinge is similar,
but without marginal teeth. The interpretation of the anterior and
posterior ends is reaffirmed by the characteristic transfer, in the
actinodont hinge, of the innermost tooth to the right valve, so that
Starobogatov's interpretation (1971) must be rejected. We provisionally

37

place here the new family Saffordiidae (with the single genus
Saffordia Ulrich 189*0 with an oval shell and terminal beak; the hinge
consists of 2 teeth in the left valve (one subumbonal and one posterior
marginal). The new family Ischyrodontidae consists of the genus
Ischyrodonta Ulrich 1890. It is characterized by the complete
reduction of the marginal teeth and presents evidence of a further
evolution in that direction, as seen in Allodesmatidae .

13. The Actinodontophoridae, differentiated to a great degree by
the subumbonal and lateral teeth, we place into a separate superfamily.
Here we also include the new family Tanaodontidae , with the single
genus Tanaodon Kirk 1927, characterized by an almost mytiloid shell,
numerous subumbonal teeth and 2-3 teeth parallel to the posterior
portion of the dorsal margin. This type of hinge represents a
transition from the actinodont to the pterineoid hinge so that a sharp
distinction of types is not possible in this case.

ik . The Anthracosiidae and the Carbonicolidae are commonly re-
garded as a single family close to Unionoidea. Starobogatov (1970)
and Nevesskaya e_t_ al . (1971) associated the Anthracosiidae with the
suborder Lyrodesmatina in view of the conchological resemblance to
the Palaeanodontidae. But Betekhtina (197*0 and Betekhtina and Shugurov
(1973) noted the difference in the type of prodissoconch between
Carbonicola McCoy 1855 and Anthracasphaerium Trueman and Weir 19*+6
on the one hand, and Anthracosia King 1856, Angarodbn Ragozin 1935,
Kemeroviella Betekhtina 197*+, Brussiella Betekhtina i960 on the other.

38

There is a difference in the hinge structure between Carbonicola
and Anthracosia (McLennon, 19*+*+; Trueman and Weir, 19*+6). This
forces us to regard the Anthracosiidae and the Carbonicolidae as
independent, although closely related, families, and we add provision-
ally to the former, Limnedmonia , new name for Pseudoedmondia Betekhtina
197*+, non Fischer 1887, with P. klepovi (Vep. 1959) as the type-species.
The hinge is anthracosiid, and the carhonicolid may be derived with
equal justification from both the lyrodesmoid and the actinodont
hinges. However, since Kolesnkiov (1977) on the basis of the micro-
sculpture, includes the Utschamiellidae , the situation is strongly
altered, since in both genera of this family there are only marginal
teeth, testifying to the affinity of the group to the suborder Actino-
dontina. It must be noted that the Nyassidae and the Archanodontidae
are provisionally placed here on the basis of the data at hand; in
spite of the similarity in appearance of the shells, it is not advisable
to reach some kind of positive conclusion regarding the systematic
placement of these families.

15- The Modiomorphidae is customarily understood to be non-
monotypic . The Coxiconchinae constitutes one group, recently set
up by Babin (1977) as a subfamily because of its unio-like shell,
with the subumbonal muscle scars remote from the beaks and a weak
one-toothed hinge. Another unit consists of the genera grouped
around Modiolopsis Hall l8*+7 and Goniophora Phillips 18U8 with a beak
noticeably anterior but a non-modiolid shell (it is rather unio-like)

39

and with a small number of subumbonal teeth. Finally a third group
consists of modioloid genera with a deep anterior muscle scar and a
considerably reduced or incomplete hinge; they are grouped around
Modiomorpha Hall and Whitefield 1869. We raise all these groups
to family rank. We do this provisionally, and are guided by the data
of Betekhtina (197*0 and Betekhtina and Shugurov (1973) regarding
the structure of the prodissoconch. We add the family Prilukiellidae
with the genera Prilukiella Plotnikov 19*+5, Sender zoniella Betekhtina
1977, and Khalfinella , new name for Microdonta Khalfin 1950, non
Be jean, 1835 as well as the Abiellidae as understood by Starobogatov
(1970); we remove Dictys Khalfin 1950 and Pseud omodiolus Betekhtina
1966, and add Abakan i ell a Betekhtina 1966, and finally Kinerkaellidae
established by Betekhtina in 1972 and characterized by its original
type III resemblance to the dorsal and ventral margins . They are
"characterized by a greater or lesser expression of the bend in the ventral
margin, close to their accompanying curve (a tendency toward the form-
ation of sinuses in the ventral and posterior margins) and a narrowing
and protrusion of the lower posterior end" Betekhtina, 1972:62 .
However, based on newer data (Betekhtina and Shururov, 1973: Betekhtina,
197*+) we accept the family not in its original extent but include only

1. The data cited are in complete agreement with the family
diagnosis.

1*0

Kinerkaella Khalfin 1950, Mrassiellina Betekhtina 1973, Degeniella
Betekhtina 1969, and, conditionally, Opokiella Plotnikov 19^9, and
Augea Khalfin 1950.

16. In the superfamily Gastrochaenoidea we include together with
the Gastrochaenidae , the new family Hippomyidae with the single
genus Hippomya Salter l86h , characterized by the smooth modioloid
shell with a wide anteroventral byssal gape, delimited posteriorly

on the lateral surface of the shell by a radial groove. Ordinarily
this genus is placed in Modiomorphidae .

17. The praecardinids are customarily set aside into a separate
order, close to the Solemyida. Still the location of the beaks un-
questionably suggest affinities to the Autobranchia. The character
of the hinge margin and the sculpture compels them to be placed close

to the lower members of the suborder Pteriina with which we also include
this group. The group customarily regarded as a single superfamily
clearly is separable in our opinion, into 3 individual super families .
In the first (Praecardioidea) the shell is equivalve (except for the
Vlastidae); in the second ( Ant ipleuro idea) the shell is sharply
inequivalve which unquestionably indicates an attached life style
(and for this reason again indicates affinities to the Autobranchia).
The subfamily Vlasinae, which we regard as an independent family, shows
considerable similarity in its shell to the structure of Lunulicardium
(the nature of the beaks, and the development of the lunule) , and this
compels us to place it in the superfamily Lunulicardioidea. In the
composition of the superfamily Praecardioidea, except the Praecardiidae

Ui

(excluding Slava Barrande l88l, Necklania Ruzicka and Prybyl 1953 and
Eopteria Billings 1865) and the Cardiolidae, often regarded as a sub-
family of a single family, we include the nev family Necklaniidae
(with Necklania and Slava), characterized by an oval, equivalve shell
with orthogyrate beaks and thin radial ribs on the surface, and also
the new family Palaeocardiidae (with Palaecardia Hall 1865 and
Amphicoelia Hall 1865), characterized by oval, dimyarian shells with
somewhat anterior beaks, without a noticeable byssal gap, and with the
outer surface covered by thin radial ribs. In the Lunulicardiidae we
include only the genera Lunvlicardium and Pterochaenia ; the other genera
which are usually placed in this family we place, together with Eopteria ,
in the order Conocardiida.

18. The "nonmarine Myalinidae" — the genera Anthraconauta
Pruvost 1930. Curivrimula Weir i960, Naiadites Dawson i860, and Papinella ,
new name for Acra Papin 1973 non Bleeker 1863, are distinguished conch-
ologically from the marine myalinids (that is, the present day ones),
which forces us to isolate them in a new independent family Naiaditidae,
characterized by an oval-quadrangular, thin shell, a comparatively
weakly projecting beak placed anteriorly but not terminally so, with
a straight and narrow hinge plate and without teeth; the surface is
covered only with growth lines. The close affinity of this group
to the myalinids was affirmed by Betekhtina (1972; 197*0- Judging
by the data regarding the early structures of the shell (? prodisco-
conch) (Betekhtina, 197^) , we should also place the family

1+2

Procopievaskiidae with the single genus Procopievskia Khalfin 1950
in this superfamily. Eurydesma Morris I8U5, in view of the structure
of the hinge margin and the shell walls, should be placed apparently in
a separate family.

19. In regard to the content of the family Pterineidae, including
the genus Pterinea (Pojeta, 1971), therein'are contained some forms
which are overall very much different in the shape of the shell and
the structure of the hinge. We propose to make further divisions of
the superfamily for those generic representatives which have an alate

or winged hinge line and different teeth (we assume that their ancestors
used to have this same kind of hinge structure). Also forms with isodont
dentition we transfer to the Order Pectinida. The genera Ahtioconcha
Oepik 1930, Pteronitella Billings 187^, and presumably Newsomella
Foerste 1930 we place, according to the work of Eberzin, into the
family Ahtioconchidae (characterized as in Pteronitella by a more
primitive hinge than in Pterinea ) . The genus Actinodesma Sandberger
I85O we put into the new family Actinodesmatidae as its shells
are distinguished by having a strongly elongated hinge border forming
projecting auricles or ears; and we also observe that the shell is also
axially and distally elongated in a ventral direction; with or without
a small or rudimentary anterior adductor muscle.

20. The Mysidellidae with an internal ligament are by no means
allied to the Mytilidae (the similarity of shell outline is superficial)
and have a clear affinity to those Pteriina which have a tendency to

^3

the formation of an internal ligament. This compels us to isolate
them in an independent superfamily the Mysidelloidea. The Pergam-
idiidae, which are similar to Mysidellidae in the structure of the shell
and the ligament, are also placed here.

21. Posidonia Bronn 1828, Posidonotis Losacco 19^2, and Aulacomyella
Furlani 1910 with a short hinge margin are sharply differentiated from
the other genera which are customarily assigned to the Posidoniidae .

In this connection they are with reason grouped into the 2 families
Posidoniidae and Halobiidae.

22. The Euchondriidae , often regarded as a subfamily of the
Aviculopectinidae because of the presence of a interrupted internal
ligament, should be placed in an independent superfamily. Another
group for placement in the same superfamily will be the new family
Crenipectinidae with the single genus Crenipecten Hall 1863,
characterized by the absence of a strong resilium and the correspond-
ing resilifer pit; the shell is pecten-shaped with a straight hinge
tooth without crura.

23. We consider it advisable to separate as new the independent
family Matheriidae (with Mat her ia Billings I858, and Heikea Isberg
193M from the Cyrtodontidae, leaving it however in the same superfamily.
This family is characterized by 1-2 subumbonal teeth in the right

valve and one in the left with a complete absence of posterior teeth,
beaks at the anterior end of the dorsal margin, so that the scar of
the anterior adductor muscle is pushed below and behind the umbo.

UU

2k. In the quite heterogeneous Cenozoic Philobryidae , a series of
genera have separate subumbonal and posterior teeth. Such a pattern
is practically identical to the cyrtodont hinge and in our opinion
testifies to the necessity of transferring these genera into the suborder
Cyrtodontina, within their own new family and new superfamily . The
superfamily Limarcoidea with the single family Limarcidae is charac-
terized by 2-3 subumbonal teeth and long oblique (slanting) teeth
which at times disappear; the valves are oval and extended dorso-
ventrally with an internal ligament. The genera placed here include
Limarca Tate 1886 and, provisionally, Cratis Hedley 191*+.

25. Another family removed from the Philobryidae (but kept in
the same superfamily and recognized as new is the Aupouriidae) with
the single genus Aupouria Powell 1937- This family is characterized
by a round-oval shell with a separate cap-shaped embryonal part, the
rest with a provinculum under the umbo, with separated gap of the
internal ligament and 2 short slanting anterior teeth. The new
family Pichleriidae is separated from the Limnopsidae into a separate
family with the single genus Pichleria Bittner I89I+. This family

is characterized by valves covered with wrinkled radial ribs, a
sharply outlined, posteriorly carinate twist and a concave carinate
basal area; the hinge plate is wide with a few slanting teeth.

26. We regard Melaxineidae as a separate family of another super-
family (Glycimeridoidea) into which, besides Melaxinea Iredale 1930,

we place Postligata Gardner 19l6 and Vasconella Boussac 1911 (the latter
is usually placed in the Limopsidae) .

45

27. Non-incubating oysters, because of the presence in them of
such morphological structures as a promyal cavity (promyal passage)
and peculiarities of reproduction, should be put into the separate
family Crassostreidae to include Crassostrea Sacco 1897, Saccostrea
Dollfuss and Striostrea Vialov, 1936. The family is characterized by
the development of a promyal cavity, the pericardium shifted before
the adductor muscle anteriorly, and to the right, and the union of
the anterior part of the suprabranchial cavity with its excurrent
part. In the left (attached) valve there is usually a deep subumbonal
cavity. The eggs develop internally, the sexes are separate (possibly
protandric hermaphrodites, but with a regular and complete sex change
phase ) .

28. In the superfamily Leiopectinoidea we place, beside the
forms customarily included here, such species as were formerly placed
in the Pteriidae, but since they possess an isodont and not a pter-
ineodont hinge, they are brought together in Palaeopteria Whiteaves
1897 and Caritodens Foerste 1910 (type-species Pterinea demissa
Conrad — for the hinge structure see Pojeta, 1971). The latter
genus is usually regarded as a synonym of Pterinea Goldfuss 1826
(Newell and LaRocque, 1969 Treatise Nl). Because of the conchological
resemblance to Rhombopteria Jackson 1890, we include that genus in
Rhombopteriidae, separating it from Leiopectinidae, where Palaeopecten
Williams 1913 and Leiopecten Khalfin 19^0 still remain; they have a
pectinoid appearing shell. The problem regarding the peculiarities

of musculature is somewhat complicated. Leiopectinidae in the extent

U6

mentioned is monomyarian. Palaeopteria and Caritodens are aniso-
myarian, and as far as Rhombopteria is concerned it is usually con-
sidered to be monomyarian, but peculiarities of the shell form permits
one to presuppose the presence here of a small anterior adductor muscle.

29. The Plicatulidae and the Spondylidae, as Yonge (1973; 1975)
showed, are quite sharply differentiated from one another, and they
differ from the Pectinidae in the structure of the ligament , foot ,
branchia and labial palps. This suggests that they be put into in-
dependent superfamilies . Yonge ' s (1975) suggested union of the plicatu-
lids and dymiids seems artifical to us. The similarity of their
features is in some cases clearly parallel (for instance, features of
the ligament ) , and in other cases they reflect the archaic features
common to the entire order (e_.g. the hinge) .

30. The old data of Ridewood (1903) regarding the branchia of
Amussium is really applicable to Propeamussium de Gregorio 188U , as
was clearly shown by R.T. Abbott (195M when he put this genus into an
independent family. It seems completely justifiable to us to associate
this family with the Pernopectinidae and Entoliidae (Waller, 1971; 1972)
but the structure of the ctenidia compels us to place all 3 families into
a special superfamily. As for Amussium Roding 1798, it is quite close

to the remaining Pectinidae (Yonge, 1973) and the question of estab-
lishing the Amussiidae as well as the remaining families of contem-
porary Pectinoidea (Palliolidae, Chlamydidae, Pectinidae) is better
left until a revision of this systematically complicated group is
undertaken.

hi

31. The Terquemiidae, as far as the appearance of the shell,
the sculpture, and the nature of the ligament is concerned is very
close to the Limariidae, compelling us to unite them into a single
superfamily. Here we also provisionally place the Chondrodontidae
Because of its similarity to the Terquemiidae and its obvious re-
lationship to the Pectinacea s.l . (Freneix and Lefevre, 1967) rather
than to the oysters.

32. The genus Heteranomia Winckworth 1922 with its type-species
Anomia squamula Linnaeus is distinguished from all Anomioidea and
similar to the Dimyoidea because of the absence of the two ascending
branchial filaments (Ridewood, 1903; Atkins, 1936; Yonge, 1977). This
compels us to place the genus into its own new family and superfamily.
The Heteranomiidae are characterized by the Anomia- like shell, with a
straight ligament and small muscle scars, a narrow cylindrical foot and
symmetrical dorsal merging of the mantle lamellae. We also include the
new family Atretidae with the single genus Atreta Etallon 1862 in the
same superfamily. It is very sharply differentiated conchologically
from Plicatulidae where it is usually placed ( Cox and Hertlein,

1969 Treatise, Nl). and extremely close to the Dimyidae (especially
Dimyodon Munier-Chalmas 1886, differing only in its monomyarian
condition. In our opinion this is a special group between the Dimyidae
and Heteranomiidae because of the similarities in the structure of the
gills. Diagnosis of the Atretidae: shell oval, inequi valve, with a
woven dorsal margin forming distinct corners with the anterior and

U8

posterior margins. The right attached valve is weakly concave without
a byssal gap, the left (free valve) is flat, both with a sculpture of
thin, divaricate radial sculpture internally. Externally along the
shell margin there is an incised crura; ligament internal in a small pit,
teeth weak, thin.; one adductor muscle present.

33. We believe that the large Palaeozoic Grammysiidae is a
combination of several different groups, phylogenetically allied
to each other and occupying a lower rank in various branches of ine
order. In the super family Grammysioidea we leave only the more prim-
itive forms, little changed by a sedentary life style. Primarily
Grammysiidae s_.s_. ( Grammysia Verneuil I8U7, Cuneamya Hall and Whitfield
1875, and Palaeocorbula Reed 1932) and secondly the Promacridae, in-
cluding Promacrus Meek 1871 and Davidia Hicks 1873 , characterized by
a longitudinal groove, elongate shell with an almost central beak,
narrow anterior end and diagonally incised posterior, with a well
developed posterior carina and without lunule or escutcheon.

We place the forms with the longitudinally elongate shell and
posterior umbo — which are apparently transitions to a burrowing
life style — (like Solenoidea) — into the super family Orthonotoidea,
which, besides the Orthonotidae , include the Sanguinolitidae with
several genera usually placed with the Grammysiidae: Sanguinolites
McCoy 188U , Grammysioidea Williams and Breger 19l8, Glossites Hall
1885, and Prothyris Meek 1871.

Into a special superfamily we place those forms which are mor-
phologically approaching the contemporary [Recent] sedentary members
of the order, with orthogyrate not strongly anterior umbos with more or

kg

less extended, "bent dorsal posterior shell end, delimited by a posterior
carina. In some of these forms there are 1-2 radial diverging plates
under the umbo. The superfamily consists of 2 families. In the new
family Protomyidae we include Sedgwickia McCoy, 188U, Cimitaria Hall
and Whitfield 1869, and Protomya Hall 1885- Its shells are characterized
by being elongated antero-posteriorly wise, subanterior beaks, concentric
sculpture, and a field weakly isolated by a carina; also the sculpture
is radial in Cimitaria . In the Cercomyidae, besides the Mesozoic
Cercomya Agassiz I8U3 — customarily placed with Laternulidae — we
include Alula Girty 1912, Leinzia Mendes 19^+9, and Solenomorpha Cockerell
1903. The family is characterized by a strongly elongate shell and,
as a rule, with a bent dorsal posterior end, narrow field sharply isolated
by a carina, elegantly sculptured on the rest of the shell surface.

3^. The superfamily Pandoroidea is clearly broken into 3 groups
which are properly themselves elevated to the superfamilial level. In
the first we find Pandoridae and Cleidothaeridae , with only an internal
ligament with a lithodesma, occasionally with some radial plates
under the umbo and with a nacreous shell without a pallial sinus. This
is the restricted superfamily Pandoroidea. In the second group
(Thracioidea) we find only the Thraciidae with an internal spoon-shaped
chondrophore , without hinge teeth or radial plates, with a non-nacreous
shell and a pallial sinus. In the third group are the 5 other families
with spoon-shaped chondrophores , occasionally with a lithodesma, without
hinge teeth but occasionally with one or 2 radial plates on the valves;

50

the shell is nacreous with a pallial sinus; superfamily Myochamoidea.

35. The superfamily Pholadomyoidea , which brings together the
members of the order which are in transition to a burrowing life style
and which thus acquire a pholadoid shell shape, is clearly divisible
into several groups, some of which we transfer to other superfamilies .
The Megadesmatidae possesses strongly protruding nymphs, orthogyrate
or weakly prosogyrate beaks, and lack a pallial sinus (Runnegar, 1965).
With these features the family approaches Edmondiidae, and thus
permits us to include it in the superfamily Edmondioidea. Thus
Myonia Dana l8U2 (with subg. Pachymyonia Dun 1932) is sharply separated
from the Megadesmatidae and should be placed in the new independent
family Myoniidae, a transition between the Megadesmatidae and the
Edmondiidae. Diagnosis of the Myoniidae: shell elongate with low
orthogyrate beaks, moderately anterior. Posterior margin obliquely
truncate with an obscure sulcus anterior to a ridged bend, strongly
developed deep pits by which the growing mantle penetrates the thick-
ness of the valves, nymphs folded externally. The Pholadomyidae as
commonly understood make up another group. The same superfamily
includes Pholadellidae (with the single genus Pholadella Hall I869),
usually placed in the Grammysiidae . The superfamily is characterized
by a shell with a pallial sinus, a strong external ligament or nymphs
and radial or divaricate sculpture combined with concentric lines on
the central field of the valves. Finally, the other families of the
superfamily Pholadomyidea [Order Pholadomyina] are characterized by the
steady submersion of the nymphs between the valves with the formation
of some sort of chondrophore . These we separate into the superfamily
Pleuromyoidea.

51

36. Humphreyia Gray 1855 should "be put into its own new family
Humphreyidae together with the Penicillidae into the superfamily Peni-
cilloidea. Diagnosis of the Humphreyidae: the tube is square in cross
section, wanting the numerous small tubes on the anterior end; walls
of the anterior widening-part form 2 united valves ; both adductor
muscles reduced.

37. To the Megalodontoidea we add 5 new families: Plethocardiidae
( Plethocardia Ulrich 189^, Eumegalodus Spriesterbach 1915, and Pinzonella
Reed 1932): shell smooth, almost equi valve, oval, with protruding
prosogyrate beaks, external ligament and comparatively narrow hinge
plate bearing 1-2 not too strong cardinals and one long lamella-like
posterior lateral tooth; Tusayanidae (with the single genus Tusayana
Stoyanow 19^8): shell smooth, circular with moderately protruding
prosogyrate beaks, external ligament and wide hinge plate with 2
cardinal teeth in the left valve (one is bifid) and one amorphous

one in right valve; one posterior lateral lamella-like tooth in each
valve; Pachyrismatidae ( Pachyrisma Morris and Lycett 1850, Pachyrismella
Cox 196U, and Protodiceras G. Boehm 1891): shell smooth, oval, with
strongly protruding prosogyrate beaks, external ligament on developed
nymphs , wide hinge plate with 1-2 strong cardinal teeth and one lateral
anterior and posterior tooth in each valve; Ferraziidae (with the single
genus Ferrazia Reed 1932): shell quadrangular, e qui valve , with strongly
protruding prosogyrate beaks, distinctly defined lunule and escutcheon,
surface with 6-7 ribs, triangular in cross section, with wide intervals

52

between them in the center of the shell, hinge plate quite narrow with
one external cardinal in each valve; Pterocardiidae (with the single
genus Fterocardia Bayan I87M ; shell quadrangular with strongly pro-
truding suborthogyrate beaks, surface covered with closely set ribs;
hinge plate wide with 1-2 cardinal teeth and anterior and posterior
lateral teeth in each valve. The last two families we place pro-
visionally in the superfamily Megalodontoidea.

38. The superfamily Hippuritoidea s_.l_. we divide into 3 inde-
pendent superfamilies guided by the character of growth of the shell.
In the Caprotinoidea, the shell grows by increasing its volume and
twisting both valves spirally (at times to a different degree) fastening
itself to the substrate by the right valve. In this group we place

the Diceratidae (as understood in the [previous recognized] sub-
family Diceratinae) , the Monopleuridae, the Caprotinidae , the Caprinidae,
and, provisionally, the Lithiotidae, which may be regarded as a lateral
branch of the rudists which have lost the hinge. In the superfamily
Requienioidea (in a number of cases the free valve acquires a lid-
like appearance) the shell is fastened to the substrate by the left
valve. Here we place the Epi diceratidae (with the subfamily Heter-
odiceratinae, Plesiodiceratinae, and Epidiceratinae) and the Requieniidae.
In the Hippuritoidea Cs_.s_. D the attached valve grows, in shape, like
a tube or a goblet, and the free valve acquires a lid-like appearance.
The attachment is by the right valve. Here we place Hippuritidae ,
Radiolitidae, and provisionally the Plicatostylidae.

39. The subfamily Opinae, which have a carinate shell with very

53

high beaks and completely lack the anterior lateral teeth, should he
separated from the Astartidae into an independent family.

Uo. Montanaria Spriestersbach 1909 should he separated from the
Mactromyidae into a new independent family Montanariidae which can be
characterized by the strongly anterior, little protruding beaks with
a lucinoid hinge and distinct anterior -lateral teeth (no posterior
ones); teeth 2 and 3 are bifid.

kl. The subfamily Euperinae, because of the fact that their young
do not hatch inside the demibranchs like the other members of the super-
family, but externally (Heard, 1965), should be elevated in rank to
a separate family. Similarly, the subfamily Sphaeriinae deserves to
be in a separate family with 2 equally developed demibranchs and central
or slightly anterior beaks. The question regarding the nomenclature
of this group is complicated. It is usually called the Sphaeriidae
Jeffreys 1862, but this is a junior homonym of Sphaeriidae Erichson
18^4-5 (Coleoptera) . The most advisable name for the family would be
the oldest, the Cycladidae, not in use for a hundred years. The
type-species of genus Cyclas Bruguiere 1798, upon which the family
name is based, should be by subsequent monotypy Tellina cornea L.
which makes Cyclas a junior synonym of Sphaerium Scopoli 1T7T-
However, Lamarck, who included this species as the only one in the
genus under this name, had in mind Cyclas rivicola Lamarck, as shown
by Keen ( 1969 , Treatise N2). It is clear that the problem should be

referred to the ICZN where it now is. In the meantime we prefer to
use the oldest name for the family.

k2. Phenacocyclas La Rocque 1950 and Illionia Billings 1875,
should be separated from the Lucinidae into the independent new
family Illioniidae, characterized by an irregular quadrangular shell
shape, suborthogyrate beaks and very long, strongly bent anterior
adductor muscle scars (there are no data on the posterior muscle
scar) .

k3. K.J. Boss (.1971) advanced a number of arguments to justify
placing Hemidonax Morch 1870 with the Cardiidae. These were uncritically
accepted by Kafanov and Popov (.1977). These arguments, in our opinion,
are insufficient mainly because the resemblance to the cardinal
sculpture, the structure of the hinge, ligament, and mantle musculature
can be fully expected also in the superfamily Donacoidea. Therefore,
until data is presented on the stomach structure — which would finally
decide the problem — we prefer provisionally to place Hemidonax into
its own family in the Donacoidea.

hk . The ideas of Ockelman (196k) on the close affinity of Turtonia
to the Veneridae, in our opinion, are based upon superficial resem-
blances, because of the evident impossibility of deriving the astartoid
stomach type from the veneroid. For this reason we put the Turtoniidae
in the superfamily Cyamoidea.

1+5. The anatomy of members of the Cyprenoididae was not studied;
however, judging by the hinge structure it is more proper, as of now,
to place them in the suborder Erycinina.

55

h6 . The Galeommatidae are quite heterogeneous conchologically ,
and this compels us to separate them into 3 separate families, keeping
them all, however, in the same superfamily. The new family Cyamion-
ematidae include Cyamionema Melvill and Standen 191^, Passya Deshayes
1898, and Triquetia Velain l8TT terror for Turquetia ] , characterized
by a quadrangular shell with beaks almost at the anterior tip; hinge
with 1-2 rudimentary subumbonal teeth; the new family Ephippiodontidae
contains only Epippiodonta Tate 1889, and is characterized by sub-
circular shells with straight dorsal margins, almost non-protruding
beaks, and 2 coextensive cardinal and external teeth; the Vasconiellidae
(with only Vasconiella Dall 1899) with an inequilateral, round-
quadrangular shell with a sinus in the center of the ventral margin;
beaks protruding, place almost centrally on the dorsal margin; one
small tooth under the umbo.

U7. The Carditidae in the usual sense should be put into a
separate superfamily. Judging by the shell sculpture and hinge, we
place the Archaeocardiidae and the Aenigmoconchidae here. The Card-
itiidae proper should be divided into h independent families: Thecaliidae,
in which the females have an internal incubatory chamber; the Cardit-
ameridae (with the subfamilies Carditamerinae, Palaeocarditinae,
Venericardiinae , and Carditesinae) with a round or oval shell, well
developed cardinal teeth of which 3b is strongly V-shaped, and more
or less well developed laterals; Carditidae with a quadrangular,
modioloid shell, protruding tooth 3b, weak tooth 3a, and without

56

lateral teeth; Miodomerididae with a shell elongated dorsoventrally ,
V-shaped tooth 3b, but without 3a, and partly submerged by the
ligament . Terraia Cox 193^ and possibly also Cowperesia Mendes
1952, because of the presence of the characteristic V-shaped, pos-
teriorly inclined cardinal tooth in the right valve is quite similar
to the Carditoidea and sharply different from Tellinoidea. Placing
them in the Carditoidea, we establish the new family Terraiidae, char-
acterized by an oval -trigonal shell, lacking radial ribs and with a
separated posterior field and noticeable anterior beaks , a strong
trigonal V-shaped cardinal tooth (3b) in the right valve, and a weakly
developed one (Ub) in the left valve.

k£> . The Permophoridae in its broad sense forms a branch of the
Order Cardita which separated early and parallels in many ways the
Carditoidea; it also is subject to division. The Redoniidae with
the genus Redonia Rouault 1851 is characterized by oval shells with
elevated and anteriorly projecting umbos, 2 cardinal teeth in each
valve and longitudinally merging posterior lateral teeth. The
Kalenteridae with the genera Kalentera Marwick 1953, Netschajewia
Yakovlev 1925 and Rimmyjimina Chronic 1952 is characterized by a
modioloform shell, reduction in the cardinal dentition (teeth de-
creasing to one in number in the valves) and evidently elongated
lateral teeth. The Permophoridae, which includes the remaining
genera of the subfamily Permophorinae, is characterized by oval or
elongate-oval shells with strongly elevated and forwardly projecting

57

umbos, two cardinal teeth in each valve (the posterior ones being the
stronger) and an elongated posterior lateral tooth. Finally, due
to a different shape of the shell and construction of the hinge, we
distinguish the subfamily Myoconchinae at the familial level. We
include under the same superfamily the family Mecynodontidae and
its representatives (Haffer, 1959) as well as the Butovicellidae
which when judged by their shells could in no way be ascribed to the
Protobranchia .

k9 . We regard the subfamily Cuninae, because of the peculiarities
of the embryonic shell, the ligament, and the hinge at the familial
level .

50. In addition to recognizing the Septocardiidae (Kafanov and
Popov 1977) as an independent family, we also elevate 2 genera to the
familial rank in the same superfamily: the Goniocardiidae (with
only Goniocardium Vasseur 1880) characterized by an askew-oval shell
with extremely well developed adductor muscles, comparatively narrow,
with toothed ribs on the posterior area, and reduced anterior cardinal
teeth; the Aviculariidae ( Avicularium Gray 1853, and presumably
Byssocardium Munier-Chalmas 1882), is characterized by a trigonal
shell with barely protruding beaks, a sharp carina, weak, smooth ribs,
strongly unequal adductor muscle and a noticeably weakened hinge; the
anterior lateral teeth are absent.

51. The traditional family Cardiidae is quite heterogeneous
conchologically as well as anatomically. If we take the latest
suggested family system (Kafanov and Popov, 1977) then 5 of the 6

58

subfamilies (Hemidonacinae is discussed in note 1+3), should be placed,
because of the structure of the stomachs, in several different super-
families just as other families are so placed, such as: Arcticidae,
Trapeziidae; Veneridae, Petricolidae ; Tellinidae, Psammobiidae;
Solenidae, Cultellidae. Inasmuch as these groups differ in shell
features and in microsculpture , they also should be reasonably regarded
as independent families. Tribes then become subfamilies. The
Limnocardiidae, according to Kafanov & Starobogatov, should be
divided into 3 groups as subfamilies, characterized by specific
evolutionary direction, and the rank of tribe should be kept for
the remaining species. The Lymnocardiinae is characterized by the
fact that its members have a submobile life style, and therefore
the anterior part of the shell is increased in size while the
anterior laterals are being strengthened. The Hypaninae takes on
a burrowing shell form, in which the siphons are well developed and
the hinge and sculpture are reduced. Finally, in Didacninae there
are forms which preserve the life style typical for the Cardioidea,
and therefore the siphons are short, the pallial sinus is absent or
weak, the hinge teeth, if reduced, are uniform.

52. In spite of the desirability of conserving the name Corbula
Bruguiere 1798 and the Corbulidae Lamarck l8l8 for the family, to do so
without a specific opinion of the ICZN would be contrary to the Code,
as is clear from the strong points raised by some recent authors
(Burch, I960; Keen 1969 Treatise N2). The situation is as follows:
the name Corbula Bruguiere is available from 1798 but no nominal

59

species were assigned to it. The first nominal species were put in
this genus in the same year (1798) by Roding, and the type-species
must therefore be selected from among these. But this would make
Corbula a junior synonym of As aphis . Thus, until the Commission
arrives at an opinion, we do not consider it advisable at present
to use Corbula (in the sense of Lamarck), as the basis for the
family name Corbulidae.

60

LITERATURE
Russian Titles

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non-marine Bivalvia. [in] Morphological and phylogenetical problems
of Paleontology. Nauka, Moscow, pp. 59-6U.

Betekhtina, A. 0. 1972. Biostatigraphy and correlation of the Carbon-
iferous [coal bearing] beds of the late Palaezoic for non-marine
bivalves. Nauka, Siberian Section, Novosibirsk, pp. 1-179-

Betekhtina, A. 0. and V. P. Shugurov. 1973. An experiment on a complex
of paleological-geochemical analysis of the Kubass coal-bearing beds,
[in] Ecology and life in the geological past (late Cambrian and
Palaeozoic of Siberia). Nauka, Siberian Section, Novosibirsk,
pp. 127-137.

Kafanov, A. I. and S. V. Popov. 1977. On the system of Cenozoic
cardioids (Bivalvia). Paleont . Zhur . 3: 55-6U.

Kolesnikov, Ch. M. 1977- The systematics and origin of limnetic fresh-
water Mesozoic bivalves. Paleont. Zhur. 3: U 2 — 5 '-+ .

Minichev, Yu. S. and Ya. I. Starobogatov. 1975- On the phylogenetic
inter-relationships of the Phylum Mollusca. [in] The Status of
the study of organic groups of the world - the bivalve mollusks.
Parts I and II. Paleontol. Inst. Acad. Sci. USSR. Moscow, Part I.
pp. 205-276.

Nevesskaya, L. A. 1965- Late Quaternary bivalves of the Black Sea:

their systematics and ecology. Trudy Paleont. Inst. Acad. Sci. USSR.
Moscow. 105: 1-390.

61

Nevesskaya, L. A. 1975- General Introduction. Short history of
studies. Contemporary status of systematic groups. CinD The
status of the study of organic groups of the world - the bivalve
mollusks. Parts I and II. Paleont. Inst. Acad. Sci. USSR.
Moscow, Part I. pp. h-^k .

Nevesskaya, L. A., 0. A. Scarlato, Ya. I. Starobogatov, and A. G.

Eberzin. 1975. New ideas on the systematics of bivalve mollusks.
Paleont. Zhur. 2: 3-20.

Scarlato, 0. A. snd Ya. I. Starobogatov. 1970. Systematics of

Bivalvia. CinU Session of reports on results of the work of 1969-
(Zoological Inst. Acad. Sci. USSR). Nauka, Leningrad. pp. h- 5.

Scarlato, 0. A. and Ya. I. Starobogatov. 1975- New data for construct-
ing a system of Bivalvia. CinU Mollusca, their system, evolution,
and significance in nature. V. Nauka, Leningrad, pp. U-8.

Starobogatov, Ya. I. 1970. Molluscan fauna and the zoogeographical
and regional divisions of the continental water bodies of the
world. Nauka, Leningrad. pp. 1-372.

Starobogatov, Ya. I. 1971. On the problem of the systematic placement
of the Ordovician bivalve Babinka. Paleont. Zhur. 3: 112-115.

Starobogatov, Ya. I. 1977- The systematic placement of the Conocardiida
and the systematics of Palaeozoic Septibranchia (Bivalvia). Byul.
Mosk. Obshch. Ispyt. prir. , otd. geologii (Bulletin of the Moscow
Naturalists Society, Geological Section). 52: 125-139.

62

Non-Russian Titles

Abbott, R. T. 195^. American seashells. New York. pp. l-5Ul.
Allen, J. A. and H. L. Sanders. 1973. Studies on deep-sea Proto-

branchia (Bivalvia) . The families Siliculidae and Lametilidae.

Bull. Mus. Comp. Zool. 1U5 : 263-309.
Allen, J. A. and J. F. Turner. 197^- On the functional morphology of

the family Verticordiidae (Bivalvia) with description of new

species from the abyssal Atlantic. Phil. Trans. Roy. Soc . London,

ser. B. 286: U01-53 1 *.
Atkins, D. 1936. On the ciliary mechanism and interrelationships of

Lamellibranchs . Part II. Sorting devices on the gills. Quart.

J. Microscop. sci. 79: 339-373.
Babin, C. 1977- Etude comparee des genres Babinka Barrande et

Coxiconcha Babin (Mollusques Bivalves de l'ordovicien) interet

phylogenetique. Geobios. NI. 1: 51-79-
Bernard, F. 1895. Premiere note sur le developpement et la morphologie

de la coquille chez les lamellibranches . Bull. Soc. Geol. France,

ser. 3. 23: IOU-I5U.
Bernard, F. 1897. Quatrieme et derniere note sur le developpement et

la morphologie de la coquille chez les lamellibranches. Bull.

Soc. Geol. France, ser. 3. 25: 559-566.
Boss, K. J. 1971. Familial affinities of Hemidonax (Bivalvia). Nautilus

85: 9-12.
Burch, J. Q. I960. Notes on the taxonomy of the pelecypod genus

Corbula Bruguiere, 1798. Veliger. 3: 33-3 1 *.

63

Casey, R. 1952. Some genera and subgenera mainly new of Mesozoic

heterodont lamellibranches . Proc . Malac . Soc. London. 29: 121-176.
Desparmet, R. , G. Termier, and H. Termier. 1971. Sur un Bivalve

Protobranche ante-areningien trouve au Nord de Wardak (Afghanistan).

Geobios. NU . 2: 1U3-150.
Dinamani, P. 1967- Variation in the stomach structure of the Bivalvia.

Malacologia. 5: 225-268.
Douville, H. 1912. Un essai de classification phylogenetique des

lamellibranches. - C. R. Acad. Sci. Paris. 15U: l677-l682.
Douville, H. 1913. Classification des lamellibranches. Bull. Soc.

Geol. France, ser. k. 12: U19-U67.
Douville, H. 1918. Le Barremian superior de Brouzet. Part 3. Les

rudistes. Paleont. Mem. Soc. Geol. France, N 52: 1-19.
Douville, H. 1935. Les rudistes et leur evolution. Bull. Soc. Geol.

France, ser. 5. 5: 319-358.
Freneix, S. and R. Lefevre. 1967 . Deux especes nouvelles de Chondro-

donta et Neithea (Bivalves) du Senonien du Taurus Lycien (Turque).

Bull. Soc. Geol. France, ser. 7. 9: 762-766.
Haffer, J. 1959. Schlossbau fruh-heterodonter Lamellibranchiaten

aus dem rheinischen Devon. Palaeontographica, A, N 112: 133-192.
Heard, W. H. 1965- Recent Eupera (Pelecypoda Sphaeriidae) in the United

States. Amer. Midland Nat. lk : 309-317-
Le Pennec, M. L. M. 1973. Morphogenese de la charniere chez 5 especes

de Veneridae. Malacologia. 12: 225-2^5.
McLennan, R. M. 19^U. Hinge structure in Carbonicola pseudorobusta

Trueman and related species. Geol. Mag. 8l: 1-lU.

6U

Munier-Chalmas , E. C. P. A. 1895. Note preliminaire sur le develop-

pement de la charnier chez les mollusques acepales. Bull. Soc.

Geol. France, ser. 3. 23: 73-80.
Narchi, W. 1968. The functional morphology of Lyonsia californica

Conrad, 1837 (Bivalvia). Veliger. 10: 305-313.
Ockelman, K. W. 196h. Turtonia minuta (Fabricius) a neotenous

veneracean bivalve. Ophelia. 1: 121-1U6.
Odhner, N. Hj . 1919- Studies on the morphology, the taxonomy and the re-
lation of recent Chamidae. K. Svenska vetensk. Akad. Handl. 59: 1-102.
Pojeta, J. Jr. 1971. Review of Ordovician pelecypods . Prof. pap. US

Geol. survey. N695: l- 1 +6.
Purchon, R. D. 1956. The stomach in Protobranchia and Septibranchia

(Lamellibranchia) . Proc . Zool. Soc. London. 127: 511-525-
Purchon, R. D. 1957. The stomach in the Filibranchia and Pseudolamelli-

branchia. Proc. Zool. Soc. London. 129: 27-60.
Purchon, R. D. I960. The stomach in the Eulamellibranchia. Stomach

types IV and V. Proc. Zool. Soc. London. 135= 1 +31- 1 +89.
Purchon, R. D. 1963. Phylogenetic classification of the Bivalvia with

special reference to the Septibranchia. Proc. Malac . Soc. London.

35: 71-80.
Ridewood, W. G. 1903. On the structure of the gills of Lamellibranchs .

Phil. Trans. Roy. Soc. London, ser. B. 19 1 * : 1^7-28U.
Runnegar, B. 1965- The bivalves Megadesmus Sowerby and Astartila Dana

from the Permian of Eastern Australia. J. Geol. Soc. Australia.

12: 227-252.

65

Sca,rlato, 0. A. and Ya. I. Starobogatov. 1978. Phylogenetic relations
and early evolution of the class Bivalvia. Phil. Trans. Roy. Soc.
London, ser, B, 28U : 217-22^.

Sanders, H. L. and J. A. Allen. 1973- Studies on deep-sea Protobranchia
(Bivalvia). Prologue and Pristiglomidae. Bull. Mus . Comp. Zool.
1^5: 237-261,

Stanley, S. M. 1975- Why clams have the shape they have, an experi-
mental analysis of burrowing. Paleobiology. 1: U8-58.

Treatise Nl. 1969. Treatise on invertebrate paleontology, Part N,
v. 1 (of 3), Mollusca 6 Bivalvia. Lawrence, pp. I-U90.

Treatise N2. 1969- Treatise on invertebrate paleontology, Part N,
v. 2 (of 3), Mollusca 6 Bivalvia. Lawrence. pp. 1+91-952.

Trueman, A. E. and J. Weir. 19^+6. A monograph of the British Carbon-
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Waller, T. R. 1971. The glass scallop Propeamussium a living relic
of the past. Ann. rep. Amer. Malac. Union for 1970. pp. 5-7.

Waller, T. R. 1972. The functional significance of some shell micro-
structures in the Pectinacea (Mollusca Bivalvia). 2Uth Intern.
Geol. congress, sect. 7. pp. U8-56.

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to hinge and ligament in Spondylus and Plicatula and a discussion
on relations within the superfamily Pectinacea. Phil. Trans. Roy.
Soc. London, ser. B. 267: 173-208.

Yonge, C. M. 1975- The status of the Plicatulidae and Dimyidae in relation
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175: 5^5-553.

66

Yonge, C. M. 1977. Form and evolution in Anomiacea (Mollusca Bivalvia]
Pododesmus , Anomia , Patra , Enigmonia (Anomiidae) , Placunanomia ,
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ser. B. 276: 1+53-527.

67

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