Jukes-Browne, Alfred John
A synopsis of the family
Veneridae

’ Coleman Library

Department of Geology
University of Toronto

UNIVERSITY OF TORONTO
LIBRARY

purchased for the

Geology Collection

from the
VARSITY PALAEONTOLOGY
FUND

With the Author's Compliments.

\
ee
a>

A Synopsis of the family

Venenide.

BY

A. J. JUKES-BROWNE, F.R.S., F.G.S.

[Yrom the Procrrpines or ran Matacoroaicat Socrrry, Vol. XI,
Parts I and II, March and June, 1914. ]

[rom the Proceepines or THE Mataconoeican Sociery, Vol. XI,
Parts I and II, March and June, 1914. |

A SYNOPSIS OF THE FAMILY VENERIDZ. PART I.
By A. J. Joxes-Browne, F.R.S., F.G.S.
Read 12th December, 1913.

Dortne the course of the past eight years I have collected and studied
the members of this family, both recent and fossil, and the results of
my studies of some of the generic groups have been communicated
to this Society from time to time. I have now prepared a general
synopsis of the whole family in order to record my final views on the
affinities and taxonomic values of the numerous groups, generic and
sub-generic, which have been recognized by different writers at
various times.

The family is a large one, and has generally been divided into three
or four tribes or sub-families. ‘Thus Deshayes, in 1853, made four
such divisions which he called Dosiniana, Meretriciana, Venusina, and
Tapesina.! Fischer, in 1887,” only recognized three such tribes,
viz. Meretricinw, Venerine, and Tapetine; but Dr. Dall, in 1902,
again proposed to make four sub-families, viz. Dosinine, Meretricine,
Venerine, and Gemmine. He rightly considered that the distinction
between Venerine and Tapetine could not be maintained; but in my
opinion the same must be said of the supposed distinction between
Dosinine and Meretricine, for the difference between the shells of
Dosinia and Pitaria is very small, and there is probably quite as little
difference between the animals. The two genera are linked together
by the sub-genera which have been described by M. Cossmann and
myself under the names of Sinodia and Cordiopsis.

With respect to the Gemmine, they are separated by Dr. Dall
because their embryos are incubated by retention within the mantle-
cavity, as in the case of Spherium and Pisidium. He calls this
viviparous reproduction, but the term is hardly correct, for, as
Professor Pelseneer has remarked, ‘‘ there are no viviparous Lamelli-
branchs, though a certain number of them appear to be so because
they are incubators.’ The fact that Gemma, Parastarte, and Psephidia
protect their young in this way is interesting, but it does not follow
that they are closely related in other respects, and we know so little
about the developmental arrangements of other genera that it seems
unnecessary at present to separate these groups from those which
seem to be their nearest allies. For instance, the shell of Psephidia
closely resembles that of Gomphina, and it is quite possible that
Gomphina incubates its embryos: we simply do not know. Con-
sequently I do not propose to recognize the Gemmine as a distinct
sub-family, believing that it is at present not convenient to make
more than two such divisions, viz. the Meretricine and the Venerine.

I had hoped that the nomenclature of the various genera and sub-
genera would have been settled before I set myself to draw up this

1 Catalogue of the Conchifera in the British Museum, London, 1853.
2 P. Fischer, Man. de Conch., Paris, 1887.

459 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

synopsis, but unfortunately this is not the case. The strict application
of the rule of priority has created many difficulties and absurdities
which were not foreseen by those who drew up the International
Code of Rules. A notable instance of such an irrational consequence
of the existing rule is that of Callista, for if this name is abandoned
the well-known group of shells which it connotes will have to take
a subordinate place, the name Macrocallista, which was proposed for
a small section of the genus, becoming the generic name, while the
really typical group would receive the name of Chionella, with an
Eocene fossil for its type instead of the well-known recent Venus
chione, which has always been regarded as its typical example.

Again, if Bolten’s Museum Catalogue is recognized as a scientific
publication, and is not excluded from the law of priority, his names
would supplant those of Lamarck, which have been in general use for
a century or more. Moreover, Bolten’s Catalogue gives no definitions
of genera or sub-genera, and is absolutely devoid of any scientific
value; while Lamarck’s genera were properly discriminated and
defined. I hold, therefore, that such a displacement of names is
unjust, unnecessary, and inconvenient, and as the Zoological
Congress has now resolved that exceptions may be made to the rule
of priority I hope that Bolten’s Catalogue may soon be declared an
exception.

Meantime I refuse to be bound by the trammels of this rule in
the strict fashion which some still advocate. I shall therefore retain
the name Callista as used by Morch in 1853 and by the Adams in 1857,
ignoring its use by Leach in 1852 with a different signification which
can never become operative. Similarly, I shall not accept the revived
use of the names Cytherea and Paphia, as proposed by Dr. Dall, who
adopts and adapts them from Bolten.

As I have described most of the fossil groups in previous papers it
will suffice for my present purpose if I mention them in their proper
places, with only brief notices of their chief characteristics. The most
ancient genera appear to be Callista, Dosiniopsis, Cyprimeria, Flaventia,
and Baroda, all of which are found in the Cretaceous deposits of
Europe and India. Pitaria appears in the Eocene, and is probably
the ancestor of Dostnia, which does not make its appearance till the
Oligocene, and then only in America, the earliest European Dosinia
being of Miocene date, though the sub-genus Cordiopsis occurs in the
Oligocene.

Dosiniopsis does not seem to me to have «any closer affinity to
Dosinia than to Callista, but it is certainly related to Sunetta through
the Eocene Jferoena; the latter, indeed, might be regarded as a
Dosiniopsis in which the posterior lateral teeth have been obliterated
by the extreme depression of the posterior border.

With regard to the shells to which I gave the name of Flaventia
in 1908, I am still of opinion that Clementia is their nearest living
representative, but the group is really a comprehensive or less
differentiated type, combining characters now found in Clementia and
Samarangia. It may also have been the ancestor of Venus and Chione,
but if so the links have not yet been discovered.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ. 60

Sub-family MERETRICIN ZA.

Genus Catuista, Morch (after Poli).

The shells of this genus were included under Meretrix (= Cytherea)
by Lamarck, but were recognized as a sub-genus by Morch in 1858,
and as a genus by the Adams in 1857. Having fully described this
group of shells in a recent paper,' and having therein given my reasons
for attaching to it as sub-genera the recent and fossil groups known
as Aphrodina, Tirelina, Transenella, and Lepidocardia, I need hardly
reprint all the descriptions there set forth, but shall merely give
a generic description and enumerate the subordinate groups.

Type, Venus chione, Linn. (fixed by Meek in 1876).

Synonyms: Chione, Gray, 1838 (not Megerle); Dzone, Gray, 1847
(not Hubner); Chionella, Cossmann, 1886.

Shell oval or elongate, smooth, striate or concentrically ridged.
Lunule circumscribed, but escutcheon not defined. Hinge of left valve
with a strong anterior lateral and three cardinals, of which the two
anterior are united at the top, and the posterior is confluent with the
nymph; in the right valve are two anterior laterals and three cardinals,
of which the two anterior are near together. Right posterior margin
always, and left anterior margin generally, grooved, the opposite
margins being bevelled to fit into these grooves. Ventral margins
smooth (except in Zransenella). Pedal scar connected with that of
adductor by a long narrow canal.

Section Callista, s.s. Type, Venus chione, Linn.

Surface glossy and vernicose, with minute discontinuous ingrained
radial striz. Pallial sinus wide, horizontal, and pointed in front.
Right posterior cardinal narrow and superficially grooved.

Section Macrocallista, Meek (1876). Type, V. nimbosa, Sol.

Section Callistina, J.-Br. (1908). Type, Cytherea plana, Sow.
(Cret.).

Sub-genera.

Lepidocardia, Dall, 1902. Type, Venus africana, Phil.

Shell small, compressed, and posteriorly attenuated. Hinge short
and teeth crowded.

Transenella, Dall, 1883. Type, Cytherea conradiana, Dall.

Pallial sinus rounded. Valve-margins tangentially grooved.

Tivelina, Cossmann, 1887. ‘ype, Cytherea tellinaria, Lam.

Small and compressed. Cardinal teeth all short. Pallial sinus
small, rounded, and ascending (Eocene).

Aphrodina, Conrad, 1868. Type, Meretriz tippana, Conr.

Cardinal teeth widely divergent. Pallial sinus deep, ascending.

Cretaceous and Eocene fossils.

Genus Amrantis, Carpenter, 1865.

Synonyms: Drone, Gray, 1847 (not 1851); Dione, Rémer, 1862;
Dione, Fischer, 1887 ; Hysteroconcha is pre-Linnean.

1 Proc. Malac. Soc., vol. x, p. 335, 1913.

61 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

Shell oval, concentrically ridged. Lunule impressed and cireum-
scribed. Escutcheon generally defined, but narrow. Hinge like that
of Callista, but the pit between the laterals of the right valve is
continued into a channel which passes under the anterior cardinal.
Pallial sinus deep and horizontal. Right posterior margin grooved,
but not the left anterior. Pedal scar opening freely or by a short
channel into that of the adductor.

Section Amiantis, s.s. Type, Cytherea callosa, Conrad.

Shell thick, glossy, and broadly ribbed over whole or part of surface.
Hinge strong, with rugose nymphs. Pallial sinus generally pointed.
This includes only three species, A. callosa, A. umbonella, Lam., and
A. purpurata, Lam.

Section Zamelliconcha, Dall. Type, Cytherea concinna, Sow.

Shell concentrically ridged. Hinge-plate excavated and attenuated
behind. Nymphs longitudinally striated. Pallial sinus obtuse or
regularly rounded. The shells known as Dione dione, D. lupanaria,
D. rosea, D. cireinata, D. unicolor, and D. cor (Hanley) belong to this
section.

Venus dione, Linn., ought to have been taken as the type of the
Lamelliconcha section, but Dr. Dall was under the erroneous
impression that Fischer had proposed the name Hysteroconcha with
V. dione as its type, whereas he merely mentioned it as a synonym of
Gray’s Dione. Dall’s Lamelliconcha only differs in the absence of
spines, which I regard asa specific and not a sectional character.

Genus Prrarta, Romer, 1857, em.

This genus was also fully discussed in the article above-mentioned,
and reasons were given for establishing the two sub-genera to which
I gave the names of Callizona and Leucothea, but it has been pointed
out to me that both these names are preoccupied and I am consequently
obliged to propose substitutes. For the tormer I propose Z%nctora
(from tincta and ora, a border), and for the latter Aphrodora (from
adpos, foam, and éwpa, a gift). I also separated a section under the
name of Pitarina. By an oversight, however, the section Agriopoma
was placed under Amiantis, instead of under Pitaria, where it properly
belongs. The following is an amended synopsis of the genus :—

Synonym: Caryatis, Romer, 1862.

Shell oval or sub-trigonal, smooth or finely striate; lunule super-
ficial; escutcheon not defined. Teeth of the left valve like those of
Amiantis, but the posterior cardinal generally more or less separate
from the nymph; in the right valve the two outer cardinals often
united to form an arch over the median. Pullial sinus short and
rounded. Right posterior and left anterior dorsal margins grooved as
in Callista. Pedal scar confluent with that of adductor.

Section Pitaria, s.s. Type, Venus tumens, Gmel.

Nymphs longitudinally striated. Left posterior cardinal confluent
with the nymph, median triangular; right cardinals separate. Pallial
sinus deep and pointed.

Section Calpitaria, J.-Br., 1908. Type, Cytherea suleataria, Lam.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ. 62

Nymphs striated. Left posterior cardinal partly free and extending
across the hinge-plate; left median triangular. Right cardinals
separate. Pallial sinus short and rounded (Kocene to Recent).

Section Pitarina, J.-Br., 1913. Type, Cytherea citrina, Lam.

Nymphs smooth; left posterior cardinal wholly free and oblique ;
outer cardinals of right valve united at top to form an arch; pallial
sinus short, rounded, and ascending.

Section Agriopoma, Dall, 1902. Type, Cytherea texasiana, Dall.

Shell dull white; nymphs smooth; left posterior cardinal long and
partly free ; outer cardinals of right valve forming a complete arch;
pallial sinus sharply angular.

Sub-genera.

Tinctora, n.n., J.-Br., 1914. Type, Cytherea vulnerata, Brod.

Synonym: Callizona, J.-Br., 1913.

Shell thick, sub-orbicular, glossy ; valve-margins crenulated ; left
posterior cardinal long and partly free from nymph; median very
thick ; pallial sinus short and rounded. Pedal scar as in Callista.

Callocardia, A. Adams, 1864. Type, C. guttata, A. Adams.

Shell very thin. Hinge-plate narrow and excavated between the
teeth. Two cardinals in each valve, united to form complete curved
arches. Left posterior cardinal long and free. Right posterior formed
of two narrow plates. Pallial line believed to be entire.

Aphrodora, n.n., J.-Br., 1914. Type, Callocardia birtsi, Preston.

Synonym : Leucothea, J.-Br., 1918.

Shell thin, white. Hinge-plate short, curved, and narrowed
posteriorly. Teeth thin and weak; left posterior short and confluent
with the nymph, right outer cardinals forming a complete arch.
Pallial sinus short and rounded.

Atopodonta, Cossm., 1886. Type, Venus conformis, Desh.

Shell small, but not thin. In the right valve the posterior cardinal
consists of two separate plates, one of which is united to the anterior
tooth, forming an arch over the median, which is bifid and A-shaped.
Pallial line entire.

Genus Lioconcna, Morch.

This genus was separated from Circe by Morch in 1853 and was
placed as a sub-genus of Meretrix by Fischer in 1887, but was adopted
as a genus by Dr. Dall (1902). I agree with Dr. Dall’s view of its
taxonomic importance, for it is undoubtedly more nearly related to
Callista than to Circe, and yet it differs from the former in several
important particulars, as will be seen from the following definition.

Type, Venus castrensis, Linn.

Shell oval or sub-trigonal; smooth or concentrically ridged. Lunule
superficial. Escutcheon not defined. Hinge-plate thick; teeth like
those of Callista, but left posterior long and partly free from the
nymph. Right posterior entire or feebly grooved. Dorsal margins
grooved as in Callista. Pallial line entire. Pedal scar confluent with
that of the adductor.

The genus includes two slightly different groups of shells; the
one typified by castrensis is nearly smooth, the other typified by

63 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

trimaculata is finely striated or grooved, and more oblique in form,
the posterior end being somewhat produced ; the latter group includes
L. suleatina, Lam., and Dione philippiana, Hanley.

Genus Saxrpomus, Conrad, 1857.

The true position of this genus as a member of the Meretricine
was established by Dr. Dall in14902.! The anterior laterals are placed
so near the anterior cardinals that they have been mistaken for
supernumerary cardinals, and the shell has consequently been located
near Zupes and Venerupis. It is, however, more nearly related to
Callista than to any other genus, and is to some extent linked with
Callista by the Japanese species C. chishumana, which has a corrugated
shell and oblique anterior lateral teeth. The dentition of Saxtdomus
differs from that of Callista much in the same way as the hinge of
Dosinia differs from that of Pitaria. The animal is said to have long
and closely united siphons.

Only three living species of Saxidomus are known, namely,
S. nuttalli, Conrad (=aratus, Gould, and maximus, Anton), S. giganteus,
Desh., and S. purpuratus, Sow. ‘They all come from the North
Pacific, ranging from California northwards to Alaska and Japan.
In time they go back to the Eocene of California.

Type, S. nuttalli, Conrad.

Shell oval, concentrically corrugated; without defined lunule or
escutcheon; slightly gaping posteriorly. Ligament large and con-
spicuous. Hinge-plate curved and narrow, with irregular teeth;
left valve with an oblique anterior lateral and three cardinals, which
are narrow and near together, the posterior being separate from the
nymph; right valve with two small anterior laterals and three
cardinals, of which only the posterior is grooved. Valve-margins
smooth and without any groove in either valve. Pallial sinus deep
and horizontal. Muscular impressions large; pedal scar opening
irregularly into that of the adductor.

Genus Dosinta, Scopoli, 1777.

This genus and its subdivisions have also been fully discussed in
a previous paper, to which the reader is referred.? Here, therefore,
I need only give a generic definition and an abbreviated synopsis of
the sections and sub-genera which I think worth recognition. The
Dosinorbis of Dall was based on D. bilunulata, which has a defined
area outside the true lunule; similar areas exist in Chione roborata
and Ch. calophylla, and are only of specific importance. The sub-
genera Sinodia and Cordivpsis may be regarded as links between the
genera Dosinia and Pitaria.

Synonyms: Orbiculus, Megerle (1811); Artemis, Poli in Oken
(1815); Asa, Leach in Basterot (1825); Aretoe, Risso (1826) ;
Exoleta, Brown, 1827. Not Dosina, Gray (1838).

Shell sub-orbicular, more or less compressed, concentrically striated

1 Proc. U.S. Nat. Museum, vol. xxvi, p. 356.
2 Proc. Malac. Soc., vol. x, p. 95, 1912.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZA, 64

or corrugated. Lunule generally small and impressed. Escutcheon
seldom well defined; ligament generally deeply sunk. Hinge-plate
deep and strong; cardinal teeth 3-3, with one anterior lateral in the
left and two small ones in the right valve; right posterior cardinal
bifid, and often a supplementary tooth-like ridge at the base of the
right nymph. Left posterior cardinal long and extending obliquely
across the hinge-plate. Right posterior margin generally grooved for
a short distance, but the left anterior only in Sinodia and Cordiopsis.
Pedal scar confluent with that of the adductor.

Dosinia, s.s. Type, D. africana, Gray.

Escutcheon depressed. Anterior lateral large and strong. Left
middle cardinal broadly bifid. Pullial sinus long, narrow, ascending.

Section Dostnella, Dall, 1902. Type, D. angulosa, Phil.

Lunule shallow. Escutcheon ill-defined. Anterior lateral small
or obsolete; left middle cardinal broad and bifid. Pallial sinus very
deep, ascending and rounded at the end.

Section Austrodosinia, Dall. Type, D. anus, Phil.

Escutcheon ill-defined. Anterior lateral strong and rugose. Left
middle cardinal entire and solid. Pallial sinus short, horizontal.

Section Phacosoma, J.-Br., 1912. Type, D. yaponica, Reeve.

Escutcheon well-defined by lamellose ridges, and the inner edges
turned up on each side of the ligament. Anterior lateral strong and
left median cardinal oblique, rugosely striated, but not bifid. Pallial
sinus deep and angular.

Section Pectunculus, Da Costa (= Orbiculus, Megerle). Type,
D. exoleta, Linn.

Escutcheon not defined. Anterior lateral small, and left middle
eardinal obscurely and unequally bifid. Pallial sinus deep, ascending,
rounded or obtusely angular.

Section Dosinidia, Dall, 1902. Type, D. concentrica, Born.

Escutcheon not defined and lunule very little impressed. Anterior
lateral small and pustular. Left middle cardinal broad and obscurely
bifid. Pallial sinus deep, angular, and ascending. Dorsal margins
not grooved.

Sub-genera.

Sinodia, J.-Br. Type, Dosinia trigona, Reeve.

Shell convex. Lunule superficial, not impressed. Escutcheon not
defined. Anterior lateral strong and distant. Middle left cardinal
solid and central. Both left anterior and right posterior margins
grooved for some distance. Pallial sinus rather short and rounded.

Since the publication of my paper on Dosinia I have discovered
that Cytherea gouldi, Reeve, belongs to this sub-genus. The type is
in the British Museum, and Mr. E. A. Smith writes that ‘‘it is
certainly a Sinodia, the hinge being exactly the same as in ¢rigona”’.

Cordiopsis, Cossmann. Type, Cytherea incrassata, Sow.

Shell thick, sub-orbicular, convex and cordiform, with prominent
incurved umbones. No lunule or eseutcheon. Left anterior lateral
small and becoming obsolete with age ; middle cardinal thick, rugose,
and central. Left anterior and right posterior dorsal margins grooved.
Pallial sinus short, sub-angular, ascending.

65 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

Pelecyora, Dall, 1902. Type, Cytherea hatchetigbeensis, Aldrich.

This shell seems to be distinguished by its rugose nymphs and
narrow angular pallial sinus. It is a fossil from the Eocene of the
United States.

Genus Dosrnropsts, Conrad, 1864.

Synonym, ora, Conrad, 1870.

Type, Cytherea lenticularis, Rogers.

Shell sub-orbicular or rounded oval. Lunule indistinct. Escutcheon
often defined and depressed. Cardinal teeth three in each valve,
separate, divergent, and entire, except the right posterior, which is
bifid. Left median strong, central, and triangular. Anterior lateral
elongate, rugose, and a simple pit for its reception in the right valve ;
a single posterior lateral in each valve. Nymphs finely granulated.
Dorsal margins not grooved. Pallial sinus rather short, ascending,
rounded or sub- angular.

This genus is extinct, and is only known from fossil representatives
in the Cretaceous and Eocene deposits. The Cretaceous species
D. subrotunda and the Eocene D. orbicularis have sharply depressed
escutcheons, and it is from them that J/eroena and Sunetta have been
derived.

Genus Sunerra, Link, 1807.

At the present day this genus is specially characteristic of the
Indo-Pacific region, but it extends round the Cape to the west coast
of Africa, as far north as Senegal. In Eocene and Miocene times
it lived in European seas, but no species has survived in the
Mediterranean area. In eastern seas it ranges from Japan on the
north to the coast of South Australia. The animal is unknown.

Synonyms: Cuneus, Megerle, 1811 (not Da Costa); Jeroe,
Schumacher, 1817.

Shell oval or sub-orbicular, sub-equilateral, rather thick, smooth
or concentrically grooved, with obscure radial riblets. Lunule
impressed and circumscribed; escutcheon narrow and deeply depressed.
Cardinal teeth 3-3, straight, separate, and touching dorsal border;
the medians fairly stout, the othe ‘rs narrow, and all generally entire ;
the left posterior ‘confluent with the nymph. Anterior laterals strong,
one in left and two in right valve. Right posterior and left anterior
marginal grooves short or obsolete. Nymphs finely denticulate.
Pallial sinus short, sub-angular, and horizontal. Ventral and lateral
margins crenulated (except in Dleroina), Pedal scar under hinge-plate
and confluent with that of the adductor.

Sunetta, s.s. Type, Donax seripta, Linn.

Shell elongate-oval, compressed or inflated, either equilateral or
posterior side the shorter. Left posterior cardinal short, right one
smooth and entire.

Sunettina, Jousseaume, 1901. Type, S. sunettina, Jouss.

Shell sub-orbicular, compressed ; posterior side expanded and rather
longer than the anterior. Left posterior cardinal long and thin, the
right one grooved at the top.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ. 66

I have not recognized the section Solanderina, created by Dr. Dall
in 1902 for S. solandri (Gray) with the brief defiintion that it is
‘‘inflated, smooth, and sub-equilateral”, because the convexity of the
valves is really the only point of difference. S. seripta is just as
smooth, S. truncata and S. karachiensis just as equilateral, and yet
both are compressed. ‘he internal characters of solandri are the
same as those of the type: the only other species which could be
classed with it is S. neglecta, Smith, but that is less inflated and is
more nearly allied to S. vaginalis, which I should refer to the section
- Sunettina.

Sub-genus.

Meroina, J.-Br., 1908. Type, Cytherea trigonula, Desh.

Shell oval or sub-trigonal, but posterior side the longer. Escutcheon
less deeply sunk, and borders less acute than in recent forms. Right
posterior cardinal grooved. Anterior laterals short and distant from
cardinals. Ventral and lateral margins smooth.

Genus Circe, Schumacher, 1817.

This genus dates from Eocene times through the sub-genera Gouldia
and Circenita, but no representative of the typical section has yet
been found earlier than the Oligocene. At the present day this group
of shells is widely distributed over the whole world, but the typical
section of Circe (s.s.) and the sub-genus Crista are only found in the
tropical parts of the Indo-Pacific region.

Synonyms: Paphia, Oken, 1815 (not Lamarck); Gafrarium, Dall
after Bolten, 1902.

Shell oval or sub-orbicular, with concentric or radiate sculpture or
a combination of both. Lunule flat, long, and narrow ; the escutcheon
when defined is very narrow. Hinge-plate deep and triangular,
with three straight, separate, and slightly divergent cardinal teeth in
each valve. Right posterior dorsal margin always grooved, but on
the left anterior side only the lunular margin is narrowly grooved.
Lower margins smooth or crenulated. Pallial line entire or slightly
sinuated. Pedal scar small, round, and separate from the adductor
(except in Gouldia).

Circe, s.s. Type, Venus scripta, Linn.

Shell compressed and flattened at the umbones, with dominant
concentric sculpture, but often divaricately ribbed on the dorsal
margins or umbonal disk. Escutcheon very narrow, and ligament
deeply sunk. Valve-margins smooth. Left posterior tooth long, the
median bifid and rugose, the others entire. Pallial line entire. ‘This
typical section includes plicatina, rivularis, undatina, and var., orbica,
tumefacta, nummulina, and lirata, Rom., but not sulcata, which belongs
to Gouldia.

Parmulina, Dall, 1902. Type, Circe corrugata, Chem.

Shell thick, sub-orbicular, much flattened on the umbonal area,
which is rugosely ribbed, the rest of the surface being concentrically
suleated or striated. Teeth generally more divergent. Ventral
margins crenulated. Pallial line entire. So far as I can ascertain

67 PROCKEDINGS OF THE MALACOLOGICAL SOCIETY.

only three species belong to this section, viz. C. corrugata, Chem.,
C. crocea, Gray, and C. intermedia, Rve. All of these live on the
Arabian coasts from the Red Sea to the Gulf of Oman, and erocea
ranges down the African coasts as far as Zanzibar, but 1 cannot
learn that any of them have been recorded from India.

Sub-genera.

Crista, Romer, 1847. ‘Type, Venus pectinata, Linneeus.

Synonyms: Paphia, Oken, 1815 (not Lam.); Gafrarium, Dall
after Bolten.

Shell not flattened at the umbones, convex or compressed, with

radial and concentric sculpture, the radials divaricate. Escutcheon
narrow and impressed, and the ligament sunken. Hinge-plate short
and triangular. In the left valve the median cardinal is grooved,
and the posterior is short. The margins of the valves are generally
but not always crenulated. This group includes C. gibbia, Lam.,
C. divaricata, Chem., C. equivoca, Chem., C. dispar, Chem., C. cuneata,
Lam., C. australis, Sow., and C. transversaria, Desh. Typical dispar
has smooth margins, while those of cwneata are crenulate; similarly,
those of transversaria are smooth and of @guivoca, which it much
resembles, are crenulate.

Circenita, Jousseaume, 1888. Type, Circe arabica, Chem.

Shell oval, convex, concentrically ribbed or striated, and without
radial sculpture. Escutcheon not defined, and ligament exposed.
Cardinal teeth small, near together, and entire; the anterior laterals
comparatively large. Ventral margins always smooth. Pallial line
slightly sinuated. This is a very small group, including only three
well-marked species, viz. arabica, Chem., lentiginosa, Chem., and
callipyga, Born, but several varieties have been given names, such as
adenensis, Phil., pulehra, Desh., splendens, Sow., semtarata, Dkr., and
funiculata, Hainer

Gouldia, C. B. Adams, 1847. Type, Circe cerina, Adams.

Shell rather small, oval, convex, with dominant concentric sculpture,
but sometimes having fine radial striation at the sides. Escutcheon
not defined. Teeth more widely divergent; right posterior cardinal
grooved, but the rest entire. Posterior dorsal margins of both valves
strongly grooved, each generally having a ridge and a groove.
Ventral margins smooth or - irregularly rugose (not crenulate). Pallial
line slightly ‘inflected, Pedal scar confluent with that of the adductor.
This group includes C. minima, Mont. (Atlantic and Mediterranean),
C. bermudensis, Smith (Bermuda and West Indies), C. sulcata, Gray
(Red Sea to Philippines and Fiji), C. nana, Melv. (Persian Gulf to
Siam), C. melvilli, Lynge (Siam), and C. amica, Smith (Pacific
Islands),

Meretrissa, Jukes-Browne, 1908. ‘ype, Zivelina depressa, Desh.
(fossil).

In 1908 I separated two species of small shells occurring in the
Oligocene of the Paris Basin under the name of Meretrisea, and
regarded them as a link between Z'welina and Meretriz. More recent
scrutiny of the specimens then sent me by M. Cossmann, and the

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ. 68

removal of some adherent sand in order to expose their pedal scars,
has induced me to change my opinion so far as the relationship to
Meretriz is concerned.

I find that in both species the pedal scar is small and separate
from that of the adductor, a feature which is not found in any
Meretricine genus except Circe. The cardinal teeth, being straight,
separate, and nearly equally divergent, also resemble those of Circe
(especially of Gouldia) quite as much as they do those of MMeretrix;
but IJeretrissa differs from both in exhibiting a small pallial sinus
which is more than a mere inflection of the pallial line, though it is
not deep.

Further, since Circe, in the forms of Circenita and Gouldia, co-
existed with Zivelina, while Meretriz has not been found in any of
the European Tertiaries, I now consider Meretrissa to be more closely
allied to Circe than to Meretriz. It may be regarded as a link
between Zivelina and Circenita, but, as the internal features resemble
the latter more than the former, I group it here as a sub-genus
of Circe.

Shell small, sub-trigonal, nearly smooth, compressed. Hinge weak
with three divergent cardinals, the anterior of the right valve
pointing to the anterior lateral pit, the median grooved, and the
posterior entire. Pallial line with a short rounded sinus. Pedal scar
separate from adductor.

Genus Mererrix, Lamarck, 1799.

This genus is very distinct both in general form and in dentition
from all the preceding genera, and it is, therefore, far from being
a good type of the sub-family to which it gives its name. The species
of which it consists are few, and they are restricted to the Indian and
Chinese seas, extending from Aden and the Gulf of Oman to Timor
and the Philippines, and as far north as Japan; but I have not been
able to find any record of its occurrence in Australian waters, nor in
the Pacific Ocean, nor have I been able to ascertain how far it reaches
southward along the east coast of Africa, but it does not exist in
Natal or Cape Colony.!

Moreover, it appears to be of comparatively. recent origin, for it
does not occur in any of the Tertiary faunas of Europe, neither can
I find that any ancestral form has been described from those of India
or Burmah. At present, therefore, it seems impossible to say when
or where it originated, but its distribution suggests that its centre of
dispersal was either from Siam or the Malay Archipelago, for most
of the species are found in that region.

1 Meretrix lusoria has been recorded from Natal by Mr. G. B. Sowerby (Journ.
Conch., 1894, p. 377), but he subsequently found that it was really
a species of Tivela, and in his Appendix to Marine Shells of South
Africa, published in 1897, he described the species under the name of
Twela alucinans. In 1903 (Proc. Malac. Soc., vol. v) Mr. E. A. Smith
identified it with Tivela natalensis of Dunker, and he informs me that
it was by mistake that the name of Meretrix zonaria was included in the
same list, the shell being really 7. natalensis.

69 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

I hope that paleontologists will give heed to the facts above
mentioned, and will not continue to record J/eretriz from Cretaceous
or Tertiary deposits when they only mean some species of ‘ Cytherea’
in its widest sense, which they cannot determine more precisely from
the external characters. In most cases it would be better to record
it as Callista (?), or else to continue the use of the name Cytherea for
indeterminate fossil forms.

Synonyms: Cytherea, Lam., 1805; Nympha, Morch, 1853.

Type, Venus meretriz, Linn.

Shell oval or trigonal, sub-equilateral, thick, generally smooth, but
sometimes concentrically lrate, with a vernicose periostracum and
a minute oblique striation on the posterior slope. Neither lunule
nor escutcheon is clearly defined. Ligament rather short and very
prominent on strong elevated nymphs. Hinge-plate thick, with
three separate cardinals in each valve diverging from a point beneath
the umbo; left posterior confluent with the nymph, right posterior
narrow and superficially grooved, others entire. Lateral teeth strong.
Both nymphs are corrugated. Ventral margins smooth. Pallial line
with a small and shallow sinus. Pedal scar confluent with that of
adductor.

The species are not very numerous, as most of those which have
received distinctive names are only colour varieties of If. meretriz,
but I should recognize the following as distinct species—petechialis,
Lam., dusoria, Chem. (= formosa, Sow.), lamarcki, Hanley, lyrata,
Sow., and exilis, Desh.

Genus Tiveta, Link, 1807.

Synonyms: Zrigona, Megerle, 1811; Zrigonella, Conrad, 1837.

Shell trigonal, sub- equilateral, s solid, smooth, with a more or less
deciduous periostracum, Lunule long, but faintly cireumsceribed.
Escutcheon not defined. Ligament very short, prominent, based on
thick nymphal plates. Cardinal part of the hinge short and triangular,
anterior part elongated. Cardinal teeth 3-3, au narrow and entire,
except the left median, which is sometimes grooved; the left anterior
points to the elongate anterior lateral, and the right anterior is close
to the lunular margin. Nymphs strongly corrugated, and sometimes
divided into a series of ridges which occupy part of the hinge-plate,
and simulate supplementary teeth. Dorsal margins grooved as in
Callista, etc. Ventral margins smooth. Pedal sear very long and
confluent with that of the adductor.

Tivela, s.s. Type, Venus corbicula, Gmel. (= V. mactroides, Born).

Ventral margins smooth.

Eutivela, Dail, 1891. Vype, 7. perplexa, Stearns.

Ventral margins crenulated. Only known from Brazil.

/

Sub-genus.

Grateloupia, Desmoulins, 1828. Type, Donax irregularis, Bast.

Synonym: Cytheriopsis, Conrad, 1838.

Shell like Zivela, but with a number of oblique parallel ridges on
the nymphs, and sometimes a thickening on the posterior dorsal

JUKES BROWNE: SYNOPSIS OF THE VENERIDA. 70

margin which simulates a posterior lateral tooth. Species occur in
the Eocene of America and the Miocene of Europe, and in the latter
they are associated with a true Zivela.

The hinge of Z%vela has been fully described by me in a previous
communication,’ in which I showed that the normal teeth are always
present, though they are often crowded into the anterior half of the
hinge-plate by the great development of the nymphal plates. The
relationship of Grateloupia was discussed in the same paper.

Genus Anrrcona, Schumacher, 1817.

This genus comprises the shells which Gray regarded as the typical
group of the Venus of Lamarck, taking the type to be Venus verrucosa,
but not himself designating it as such.* In this view he was followed
by Deshayes (1853) and the Adams (1857), and they all included the
genus in the sub-family which possesses an anterior lateral tooth.
Romer, however, in 1867 introduced confusion by regarding the
group as part of the genus Chione, not even distinguishing it as
a separate section, but grouping the species in the same section as the
typical Chione under the name of Omphaloclathrum. Paul Fischer
(an 1887) adopted Rémer’s method of classification, and most French
geologists have followed in his footsteps, so that even such con-
chologists as Cossmann:and Peyrot include the Antigona group
under a comprehensive Chione genus, though they do separate it as
a section under Morch’s name.

In America Dr. Dall has followed the English view of complete
generic distinction, and has placed the two genera in separate sub-
families. Unfortunately, however, he has revived the abandoned
name of Cytherea from Bolten’s catalogue, and has applied it to this
genus with V. puerpera asa type. Hence, though agreeing with his
recognition of the genus, I cannot accept his nomenclature.

Of course, the whole question of generic difference depends upon
the structural importance of the small tooth on the front part of the
hinge-plate. Romer must have regarded it as a mere excrescence,
and not as a definite anterior lateral, though how he could possibly
hold such a view with regard to Ant. lamellaris (=A. lamarchi, Gray)
is really incomprehensible. The fact is that different species of
Antigona show every gradation between the well-developed laterals
of A. lamellaris (in both valves) and the little pustular tooth in the
left valve of A. reticulata, which looks like an outgrowth from the
anterior cardinal and has no corresponding pit in the right valve.
Yet comparison with other species shows that the pustule is
undoubtedly an atrophied anterior lateral, apparently in process of
being crowded out by a shortening of the hinge-plate and the greater
development of the anterior cardinal.

It may, of course, be argued that the Chzone group has been evolved

! Proc. Malac. Soc., vol. x, p. 266, 1913.
2 See my discussion of the name Venws in Proc. Malac. Soe., vol. ix,
p. 242, 1911.

71 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

from Antigona by the gradual elimination of the anterior laterals,
and I am quite disposed to think that such has been its origin; but
our genera are established for the sake of convenience in classification,
and not for the purpose of expressing a theory. There is no difficulty
in distinguishing the two groups and in recognizing them as genera,
and they have “certainly had a separate existence ever since the
Miocene period. In the recent forms the anterior lateral is persistent
from youth to full age, and if there are fossil forms in which it
disappears with growth, they must be allocated on the sum of their
other characters, but I do not know of any.

Here I must correct an error into which I fell in 1908 when
describing the Veneride of the Eocene and (ligocene deposits. An
Oligocene shell described by M. St. Meunier under the name of Venus
loewyv* was then ascribed to the genus Chione, because M. Cossmann
had referred it to that genus, and because reference to the published
figures seemed to show that such reference was correct. Recently,
however, by the publication of MM. Cossmann & Peyrot’s Conehylio-
logie Néogénique de U’ Aquitaine, I became aware that their genus
Chione was the antiquated conception of Romer, and that it included
the groups of Clausina, Omphaloclathrum, etc. In reply to inquiry
M. Cossmann informs me that his valves of Venus loewyi show
a distinct anterior lateral tooth in the left valve and a pit for its
reception in the right. It is clear, therefore, that the shell is a species
of Antigona, and does not belong to Chione; it follows, moreover,
that Antigona dates from the Oligocene period, and that Chione does
not, so far as we yet know.

It may also be stated that the Ventricoloidea of Sacco (1900)?
appears to be a synonym of Artena, Conrad (1870).° The type of the
former is Cytherea multilamella, Lam. , and having compared specimens
of this shell, which I owe to the kindness of Professor Peyrot, with
the descriptions and figures of Artena given by Dr. Dall, I have no
hesitation in saying that it accords with Artena in all essential
particulars. As Dr. Dall remarks, a bears the same relation to
the typical Antigona (A. lamellaris) as Ventricola does to the group
which he calls Cytherea (i.e. A. puerpera), and this I understand to
be exactly the idea which Professor Sacco wished to express.

It is unfortunate that the genotype of Antigona (V. lamellaris,
Schum.) is so different from all the other recent members of the
genus that it stands by itself. It is one of the absurd results created
by the plan of fixing genera by ‘types’, and by the rigid rule of
priority that the so- called ty pical ‘section of a large genus may
include only one species! This, however, makes no difference to the
definition of the genus as a whole, and I therefore give such
a description before indicating the various divisions of it.

1 Nouv. Arch. Mus. d’Hist. Nat. Paris, sér. 11, tom. iii, p. 235, pl. xiii,
figs. 11, 12.

2 I Moll. Terz. Piem.; pt. xxviii, p. 80, 1900.

% Amer. Journ. Conch., vol. vi, p. 76.

~]
we

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ.

Antigona, Schum., 1817.

Synonyms: Dosina, Gray, 1838; Venus, s.s., Gray, 1847, and
Deshayes, 1853; Omphaloclathrum, Morch, 1853; Venus (Antigona),
E. A. Smith, 1885 (Challenger Report); Cytherea, Dall (after
Bolten), 1902.

Shell convex and generally globose, with prominent concentric
lamelle and sometimes with radial sculpture. Lunule and escutcheon
both clearly defined. Umbones prominent and incurved. Inner
margins crenate. Hinge thick and teeth strong; each valve with
three divergent cardinals, of which three are grooved, and the posterior
of the left valve is confluent in the nymph. The anterior lateral of
the left valve is often small and papillose, and those of the right are
obsolete. Pallial sinus short, either angular or rounded. Pedal scar
generally separate from that of the adductor.

Antigona, s.s. Type, Cytherea lamellaris, Schum.

Shell oval, with strong concentric lamelle, crossed by radial riblets.
Lunule impressed, and escutcheon defined in both valves. Ligament
exposed. Teeth widely divergent, and both anterior cardinals
directed forward ; a strong anterior lateral in the left, and two small
ones in the right valve. Nymphs long and striated. Pallial sinus
small and acutely angular.

Artena, Conrad, 1870 (= Ventricoloidea, Sacco, 1900). Type,
Venus straminea, Conrad, 1842 (not of Conrad, 1837).

Shell oval, globose, with sharp concentric lamelle, and striated
interspaces, but no radial ribs. Left anterior lateral well developed,
and two strong laterals in the right valve with a long, deep pit
between them. Other teeth normal. Pallial sinus small and angular.

The type is an American Miocene fossil. European species are
Venus loewyi, Meun. (Oligocene), Cytherea multilamella, Lam.
(Miocene and Pliocene), Venus burdigalensis, Mayer (Miocene).

Sub-genera.

Periglypta,' J.-Br., 1914 (= Cytherea, s.s., Bolten in Dall).
Type, Venus puerpera, Linn.

Shell cancellated by strong concentric ridges crossed by radial riblets
which crenulate the ridges. Escutcheon narrow, and the right half
overlapping the left. Ligament deeply sunk. Nymphs usually
having a finely rugose area. Anterior lateral very small and close to
the anterior cardinal. Pallial sinus usually wide and rounded.

This group includes the following species which are currently
known as ‘ Venus’: V. reticulata, Linn., V.crispata, Desh., V. listera,
Gray (W. Indies), V. elathrata, Desh., V. sowerbyi, Desh. (E. Indies),
V. multicostata, Sow., and V. monilifera, Sow. The forms known as
lacerata, Hanley, magnifica, Hanley, and reticulata, Sow., are probably
only varieties of puerpera. Two other species, V. laqueata, Sow., and
V. chemnitzi, Hanley, differ from all the rest in the following

1 From tept, very much; yAu7ros, carved.

73 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

particulars: they have smooth nymphs, a small angular sinus, and
the pedal scar is confluent with that of the adductor.

Clausina, Brown, 1827. Type, Venus verrucosa, Linn.

Shell oval or rotund, globose or compressed, with dominant
concentric structure. Lunule and escutcheon well defined, the latter
being unequally divided between the valves. Teeth less widely
divergent than in Periglypta, but normal, except that the anterior
lateral is small. Nymphs smooth. Pallial sinus always small and
angular.

Clausina, s.s. Inflated and often globose, concentric ridges
crossed by irregular radial riblets which sometimes become nodular
prominences. Left anterior lateral very small and pustular; right
laterals and pit often becoming obsolete. Pedal scar large, oval and
separate from adductor scar.

Only afew species can be included in this group, viz., V. verrucosa,
Linn. (with the vars. canariensis and rosalina), V. nodulosa, Sow.,
V. toreuma, Gould, V. jukes’, Desh., and V. fordi, Dall.

Ventricola, Romer, 1857. Type, Venus rigida, Dillw. (=rugosa,
Chem.).

Shell globose or merely convex, ornamented with numerous regular
concentric lamelle with striated interspaces and sometimes weak
radial striz on the posterior slope. Anterior denticle and its corre-
sponding pit both persistent. Pedal scar confluent or opening by
a channel into the adductor scar.

This group includes V. casina, Linn., V. foveolata, Sow., V. oblonga,
Hanley, V. declivis, Sow., V. lyra, Sow., V. effossa, Phil., V. strigillina,
Dall, V. magdalena, Dall, V. rugatina, Heilprin (if not vars. of rigida).

Circomphalus, Morch, 1853. Type, V. plicata, Gmel. (fixed by
Sacco, 1900).

Shell compressed with flattened umbones, encircled by distinct
concentric lamelle which pass posteriorly into expanded elevations.
Hinge-plate much curved and attenuated posteriorly. Anterior
lateral very small and often impersistent; pit in the right valve
obsolete. Pedal scar rather small, nearly separate, but connected
with the adductor scar by a narrow channel.’ Valve-margins very
finely crenate.

The name Circomphalus was adopted by Morch from Klein, and
applied to the following small group of shells: V7. peruviana, Sow.,
V. dysera, Linn. (= plicata, Gmel.), V. calophylla, Phil., V. tiara,
Dillw., and V. berry, Gray. In 1857 the Messrs. Adams also
adopted it for the same group, and included many other species allied
to V. tiara, but without indicating any one as a type. In the same
year Rémer proposed the name Anaitis for what was practically the
same group, but this name was preoccupied by Duponchel in 1829,
and cannot therefore be used.

No one seems to have selected a type for Circomphalus until 1900,
when Professor Sacco definitely indicated V. plicata, Gmelin, as the
type of a small group including V. lamellata and V. calophylla, but
without giving any diagnosis, merely remarking that its members
were species which could not be referred to other sub-genera such as

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZE. 74

Chione, Clausinelia, and Anaitis.!. In 1902 Dr. Dall gave V. plicata
as the type of Circomphalus, but without reference to Sacco or to
anyone else in explanation of such a selection.?

It is much to be regretted that the name should thus come to be
attached to V. plicata instead of to some member of the teara group,
for which it was evidently intended both by Morch and by H. & A.
Adams. They only included V. plicata in that group because they
supposed it to resemble the rest in having no lateral teeth, or
because they did not regard the small anterior tubercle as a normal
tooth.

Neither V. /amellata nor V. calophylla can be grouped with V. plicata,
for neither of them shows any trace of an anterior lateral even in very
young shells, and through the kindness of Dr. J. C. Verco, of Adelaide
(S.A.), I have been able to examine young shells of both these species.
Another shell which much resembles V. plicata in external characters
is V. yatesi, but the specimens which I have seen show no trace of
an anterior denticle. Indeed, so far as I can ascertain there is no
other recent species which can be associated with the type of
Circomphalus. There are, however, several species in the Miocene
and Pliocene deposits of France, Italy, and Austria which certainly
belong to it; these are V. subplicata, @’Orb., V. basterott, Desh.,
V. dertoparva, Sacco, and V. scalaris, Bronn. By Messrs. Cossmann
and Peyrot these species have been referred to the Clausinella section
of Chione, but that must be reserved for the shells which have no
rudiment of a lateral tooth, as there is none in C. fasciata which is
the type. The other species which they associate with V. plicata
I should refer to Ventricola; these are V. casinoides, V. fasciculata,
and V. haidingert. Professor Sacco has figured many varieties of the
above-mentioned species, but I do not think he has correctly referred
all his specimens to their proper species, for he evidently regards the
anterior denticle as of no importance even in the distinction of
species.

I am quite prepared to admit that the fase/ata and tiara group has
probably been derived from the plicata group by the elimination of
this anterior lateral, but I regard the retention of the lateral tooth
as a feature of generic importance. This question will be further
discussed in the sequel.

1 I Moll. Terz. Piem., pt. xxviii, 1900.
2 Proc. U.S. Nat. Mus., vol. xxvi, p. 356, 1902.

A SYNOPSIS OF THE FAMILY VENERIDA. PART I.
By A. J. Juxxs-Browne, F.R.S., F.G.S.
Read 18th March, 1914.

I wave followed Gray and Deshayes in dividing the Veneride into
sub-families, but into two only, the Meretricinz and the Venerine,
according to the presence or absence of an anterior lateral tooth. By
this criterion the genus Antigona is separated from the genera Venus
and Chione, but I do not wish it to be supposed that I regard these
two sub-families as two distinct lines of evolution. On the contrary,
I think each series includes several stirpes or branches of development,
and I think that the Chione group has been developed directly from
the Antigona stock by suppression and elimination of the anterior
lateral tooth.

On this point [ again find myself in disagreement with Dr. Dall,
who imagines that there are important anatomical differences between
the animals of Chione and Antigona, and thinks that the possession of
an anterior lateral is correlated with such differences. In his own
words, ‘‘there is not @ priort any very good reason why the presence
or absence of a minute pustule of shelly matter in front of the cardinal
teeth should count for much in the classification of species (or) genera,
or still less be the criterion for determination of the sub-family to
which a species belongs. Yet in making comparisons of the anatomical
features of these animals this little tooth or pustule is found an
excellent index to important anatomical differences. So, whether
it has any intrinsic value or not its correlation with important
characters must be admitted.”’?

Dr. Dall, however, does not state what these characters are or how
the animal of Antigona, which he calls Cytherea, differs from that
of Venus and Chione. He only states under the head of Meretricine
that they have ‘‘siphons of moderate length with papillose orifices,
the tubes united for a great part of their length, the margin of the
mantle largely free, more or less papillose, the foot large, hatchet-
shaped, not byssiferous’”’; and that in the Venerine ‘the siphons
are usually comparatively short and more or less separate from one
another. ‘The foot is hatchet-shaped, and in the adult not byssiferous
except among the nestlers’”’. He might also have added that the
mantle-margins are free and generally fringed, and that the orifices
of the siphons are often cirrhose; and he should have said that the
length of the siphons varies much in different genera.

It will be seen, therefore, that in the characters which are generally
considered to bei of importance for the purposes of comparison there
is no essential difference between the animals of the Meretricine and
Venerine, unless he intended to signify that the siphons of the latter
are always more separate than those of the former. On this point

1 Trans. Wagner Free Inst. Science, vol. iii, pt. vi, p. 1281, 1903.

JUKES-BROWNE: SYNOPSIS OF THE VENERID®. 76

I have made inquiries, more particularly in regard to the Antigona
and Ventricola group, with the following results : in Clausina verrucosa
the siphons are said to be completely separate, but there is no record
about those of Ventricola casina; I therefore applied to Professor
Herdman, who kindly informs me that in this species the siphons are
united for a great portion of their length, i.e. for about half their
extension outside the shell. Again, to Mr. H. Suter, of New Zealand,
I owe the information that Ventricola oblonga has ‘short and rather
small siphons which are united to their tips”. There is, therefore,
great variation with regard to the union of the siphons in this genus.

There seems to be an equal lack of uniformity in the Venus and
Chione group, though they are usually united for about half their
external length. ‘This is the case in Venus mercenaria as figured by
Dr. Dall himself;! also in Chione gallina and Ch. fasciata, but in
Timoclea ovata they are united for three parts of their length, and
it is stated that the same is the case with some varieties of Ch. gallina.
In the case of Ch. grus, moreover, a West Indian species, Dr. Dall
himself states that ‘‘the animal has two subequal closely united
fringed siphons’’, so that his own statements are inconsistent with
one another.

The facts above are sufficient to dispose of the theory, stated by
Dr. Dall as if it were a proved fact, that there is any correlation
between the anatomical characters of the animals and the presence or
absence of an anterior lateral tooth on the shell. On the other hand
I am decidedly of opinion that this anterior pustule or ‘dentelon’
has an intrinsic value of its own, for if it is the vestigial relic of an
anterior lateral tooth, then it represents an important structural
element in the dental armature of the hinge-plate.

It may of course be argued that if Venus and Chione may be
descended from species of Antigona they should not be placed in
different sub-familes, and to this there is no answer except that no
sub-families could then be recognized, and that it does seem useful
to emphasize the importance of looking for this little tooth, and of
using it as a basis of classification.

Among the Venerine the groups which I recognize as having the
rank of genera are—Venus, Protothaca, Samarangia, Gomphina,
Gemma, Clementia, Cyclina, Cyprimeria, Marcia, Tapes, Paratapes,
Baroda, and Venerupis. A few remarks on the taxonomic values of
certain groups may be useful to explain the connotation of these
genera and some of their divisions.

In the first place I do not find any differences of real generic
importance between Venus (= Dercenaria) and Chione, so that I rank
the latter as a sub-genus of the former; nor is there any good reason
for the generic separation of Anomalocardia, which combines some
characters of Mercenaria with some of Chione. As a matter of fact
it would be more reasonable to separate those Chione which are
destitute of radial sculpture, such as roborata and tiara. It seems
more natural and convenient, however, to regard all these three

1 Bull. U.S. Nat. Mus., No. 37, pl. lv, 1889.

77 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

groups Chione, Anomalocardia, and Clausinella as sub-genera of
a comprehensive genus Venus.

With regard to Zimoclea, of which the type is Venus ovata, Pennant,
I am convinced that it cannot be separated from the typical section
of Chione either solely or principally on the ground of its external
sculpture. There is every gradation between the cancellated forms
of Chione and the Zimoclea type, in which the concentric ridges are
reduced to scales or nodes on the radial ribs. The distinction must
be found in other points of difference, and Venus ovata can be grouped
with other species which have a similar ovate sub-equilateral shape,
the same widely divergent teeth, with an obtuse or rounded pallial
sinus; I also find that in all these species the pedal scars are separate
from those of the adductors, while in the typical section of Chione
there is almost always an open connexion between the two sears,
which means of course a more or less complete union of the pedal and
adductor muscles.

In this connexion it is curious to find that M. Cossmann has
proposed to make Zimoclea a separate genus, but this estimate of its
importance is partly due to his confusion of Chione with Antigona.
Moreover, he relies entirely on the characters of 7. ovata, and con-
sequently he does not give such a comprehensive definition of Timoclea
as would make it comprise such species as V. marica, V. striatissima,
V. subnodulosa, and V. arakanensis. It may be noted also that the
straight inner border of the hinge-plate, which he mentions as
distinctive, is largely a function of the sub-equilateral shape of the
shell, for an oblique curvature of the shell naturally produces
a curvature of the hinge-line.

Again, the differences between the Clausinella of Gray and the
Lirophora of Conrad (which should have been written Lirifera) seem
to me so small and unimportant that no good purpose can be served
by laying much stress on them. ‘The real fact is that these names,
through the types attached to them, belong to exceptional forms of
a large natural group. Thus Venus fasciata is a European form,
which, in its compressed shape and its sculpture of broad flattened
ridges, stands quite by itself, while Conrad’s type was a fossil nearly
allied to the West Indian Venus paphia, Linn., a species in which the
ridges pass into erect posterior expansions, and also exhibit an obscure
radial striation.

Now the natural group to which these species belong is that
typified by Venus tiara, Dillwyn, V. berryt, Gray, and V. roborata,
Hanley. It was this group for which Morch, in 1853, used Klein’s
name of Circomphalus, and if subsequent writers had only taken note
of this (Tryon, Sacco, and Dall) they would not have chosen V. plicata
as the type (see ante, p. 73). The name Clausinella, however, was
published in 1851, and has priority, so that obviously the best course
to pursue is to adopt it for the whole natural group, though Lirophora
may be used for the few recent American shells which conform to
Dr. Dall’s definition, and for their fossil representatives.

Venus gallina, the type of Morch’s Chamelea, is another exceptional
form which is allied to the V. tiara group, and seems to be connected

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ. 78

with it by some fossil species, both in Europe and America. It may
therefore be regarded as a section of Clausinella, which will thus
become asub-genus of as much importance as Chione. In this apprecia-
tion of Clausinella I find myself in accord with Messrs. Cossmann and
Peyrot, but they have made the mistake of including V. plicata in
the group and several fossil species which do not belong to it.

My reasons for the elevation of the group named Protothaca by
Dr. Dall to the rank of a genus will be given in the sequel, but,
briefly stated, they are that when one species included in the group
by that author has been restored to Chione, and another one to Zapes,
the remainder form a small genus which can be satisfactorily defined,
and which seems to be intermediate between Chione and Zapes.

Under the head of Clementia it will be found that I have separated
certain recent species as a new section with the name of Terentia, and
I desire to thank Mr. MacAndrew for giving me the opportunity of
examining his specimens of these rare species. ‘The Cretaceous
fossils, for which I created the sub-genus FVaventia in 1908, have
again occupied my attention, and the examination of the interior of
a left valve of 7. ovalis, preserved in the Royal Albert Museum at
Exeter, has confirmed my opinion of the relationship between
Flaventia and Clementia.

I have included Clementia and Cyciina in this sub-family because of
their conchological characters, which, in the Lamellibranchs and for
the purposes of classification, I consider to be of more importance
than the small differences which are observable in the animals within
the limits of a family. I am aware that Deshayes described the
animal of Clementia papyracea as resembling that of Dosinia, and as
having completely united siphons and a compressed hatchet-shaped
foot; so that if we trusted to the characters presented by the
animal of this species we might place Clementia in the Meretricinz
near Dosinia or Pitaria, which latter, according to Adanson, has an
animal of similar structure.

But we have no detailed information about other species of
Clementia, except that Dr. Dall has recently stated! that the animal
of Cl. subdiaphana (an American species) is ‘veneroid’. He does
not explain what he means by this term, but it can only mean that
the siphons are wholly or partially free and that its foot is tongue-
shaped, and he has consequently referred this species to his genus
Marcia (i.e. Samarangia). There can be no doubt, however, that the
shell and dentition of C. subdiaphana is more like that of Clementva
than that of Samarangia, and that it is still more different from the
fossils called Venerella by Cossmann. Hence I agree with Carpenter
in regarding subdiaphana as a species of Clementia, akin to C. vatheleti
and C. cumingi, and, if their animals differ from that of C. papyracea,
it may be convenient to establish them as a section or sub-genus.
Probably, however, the differences are no greater than those which
exist between different species of Zapes, as will be made manifest in
the sequel.

' Nautilus for January, 1914, p. 103.

79 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY,

I have made a careful investigation of the shells which have
hitherto been included in the genus Zapes, with the result that
I propose its division into two genera and the transference of the
T. pullastra group to the genus Venerupis. The reasons for this are
discussed under the head of Zapes.

Genus Venus, Linneus.

Animal with frilled or fringed mantle-margins. Siphons rather
short and united for half their external length or more. Foot
linguiform, thick or compressed, often extensile.

Shell oval or sub-trigonal, more or less inequivalve. Lunule and
escutcheon generally well defined. Sculpture concentric or cancellate.
Hinge-plate thick, with three divergent teeth in each valve, the left
posterior being long, narrow, and adherent, or adjacent to the
nymph. Pallial sinus small. In the right valve the posterior dorsal
margin is always grooved, but in the left there is seldom any groove.
Ventral margins crenulated.

Sub-genera.

Venus (s.s.), Lamarck, 1799. Type, V. mercenaria, Linn. Synonym:
Mercenaria, Schumacher, 1817.

Shell ovate, convex, solid. Sometimes nearly smooth, sometimes
ornamented with thin, concentric lamelle and by faint radial striation
on the posterior side. Teeth not widely divergent, not occupying
more than a right angle; left anterior straight, right posterior and
both medians generally grooved. Pedal scar separate from the
adductor, with a thread-like channel between them. Pallial sinus
triangular.

This group is restricted to the coasts of North America and Japan ;
it includes V. campechiensis, Gmelin (= mortoni, Conrad, and
fulgurans, Vryon), V. kennicotti, Dall, V. apodema, Dall, and
V. stimpsoni, Gould. Geologically it dates from the Oligocene,
and several species have been described by Conrad and Dall from
the Miocene and Pliocene of the United States.

Chione, Megerle, 1811. Type, Venus cancellata, Lam.

Shell oval or sub-trigonal, oblique or sub-equilateral. Sculpture
always comprising concentric and radial elements. Hinge-plate
short, teeth becoming solid and entire with growth, but both medians
grooved when young, each set generally widely divergent.

Section Chione (s.s.). Shell oblong or obliquely trigonal, inequi-
lateral, umbones prominent. Sculpture cancellate. Lunule and
escutcheon always well defined. Pallial sinus small and angular.
Pedal scar confluent with that of adductor. Marginal crenulation
sometimes obsolete posteriorly.

This section includes granulata, Gmelin, pectorina, T.am., sub-
rostrata, Lam., crenulata, Sow. (= pubera, Val.), grata, Say
(= histrionica, Sow.), undatella, Sow., succineta, Val., pulicaria,
Brod., amathusia, Phil., gnidia, Brod. & Sow., asperrima, Sow.,
columbiensis, Sow., subrostrata, Lam., compta, Sow., and stutchburyi,

JUKES-BROWNE: SYNOPSIS OF THE VENERID®., 80

Gray. These are all American species except the last, which is
‘a New Zealand shell.

Section Zimoclea, Brown. Type, Venus ovata, Pennant.

Shell oval and nearly equilateral, the umbones being generally
sub-central and not prominent. Sculpture cancellate, and the radials
sometimes stronger than the concentric ribs. Hinge-plate straight,
and the anterior teeth directed forward so that there is a wide
divergence. Nymphs high and rather short. Pallial sinus obtuse or
rounded. Pedal scar separate from the adductor. Valve-margins
strongly crenulated all round.

This section includes the following species—lagopus, Lam., gallinula,
Lam., australis, Sow., costellifera, Ad. & Kve., scabra, Wood,
striatissima, Sow., marica, Linn., recognita, Smith, arakanensis, Sow.,
subnodulosa, Sow., stamensis, Lynge, micra, Pilsbry, zmbricata, Sow.,
lionata, Smith, pygme@a, Lam. ‘The only American species known to
me which can be referred to Zimoclea (as above defined) is pygmea,
which has an obtuse sinus and a separate pedal scar, though it is far
from being equilateral.

Anomalocardia, Schum., 1817. Type, Venus flecuosa, Linn.

Synonyms: Zriquetra, Anton after Blainville, 1818 ; Cryptogramma,
Morch, 1853.

Shell trigonal, convex, posteriorly attenuated and angulated.
Sculpture mainly concentric, in broad rounded ribs crossed by finer
radial riblets. ‘Teeth solid and widely divergent. Nymphs rugose.
Pallial sinus very small and sometimes obsolete. Pedal scar opening
narrowly into that of adductor.

This is a small section only, including the species flexuosa (Linn.),
brasiliana, Gmelin (=macrodon, Hanley), euneimeris, Conrad (=rostrata,
Sow.), subimbricata (Sow.), subrugosa (Sow.), puel/a (Pfeiffer), and
leptalea (Dall). All these, except the type, are American species.
Dr. Dall regards Venus squamosa, Linn., as an Anomalocardia, and
separates it as a section under the name of Anomalodiscus, but in my
opinion both it and subrostrata, Lam., belong to the typical section of
Chione, for I see no difference except in shape. On the other hand,
Venus impressa, Hanley, has smooth ventral margins as well as smooth
nymphs, and is consequently a remarkable exception to the crenulated
margins of the genus. It might be regarded as a section with the
name of Cryptonema, in allusion to the concealment of the radial
striation along the margins.

Clausinella, Gray, 1851.

Synonyms: Crrcomphalus, Morch, 1858 (no type specified) ; Anaitis,
Romer, 1857 (in part), not of Duponchel, 1829.

Shell with dominant concentric sculpture of strong ribs or ridges,
radial striation being absent or obscure. Teeth widely divergent and
solid in the adult, though the medians are often feebly grooved in
young shells. Lunule and escutcheon well defined, but the latter
more marked in the left valve. Nymphs striated and sometimes
rugose. Pallial sinus very small, angular or rounded. Pedal scar
very narrowly connected with that of adductor.

Clausinella, s.s. Type, Venus fasciata, Da Costa.

81 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

Shell sculptured in regular concentric ridges, which do not rise
into erect lamellae, and seldom show any radial striation. Inter-
spaces finely concentrically striated. Nymphs with one or two
longitudinal strie.

The majority of the species belonging to this section occur in the
Indian, Australian, and Pacific regions. They include tiara, Dillw.,
foliacea, Phil., roborata, Hanley, isabellina, Phil., berryt, Gray, and
roseotincta, Sow. In Kurope it dates back to the Helvetian stage
of the Miocene (V. dertoparva).}

Lirophora, Conrad, 1864. Type, Venus athleta, Conrad.

Shell sculptured in thick concentric ridges, which are rounded in
the centre, but pass into erect lamelle posteriorly, and often show
radial striz on their ventral sides. The interspaces are concentrically
striated. Nymphs more or less rugose.

This group is chiefly American, and includes V. paphia, Linn.,
V. maria, VOrb., V. peruviana, Sow., and V. kellettit, Hinds. In
Florida it appears to date back to the Oligocene, and there are many
Miocene species.

Chamelea, Morch, 18538. Type, Venus gallina, Linn.

Synonyms: Ortygia, Brown, 1827 (not of Boie, 1826); Hermione,
Leach, 1852 (not of Blainville, 1828); Chamelea, Adams, 1857.

Shell sculptured in narrow close-set concentric rounded riblets,
which are often oblique and irregular; the radial striz are sometimes
faintly visible. Nymphs nearly smooth. Pallial sinus angular.

V. interpurpurea, Conrad, of the Caribbean Sea, and V. crassa,
Q. & G., of New Zealand, may be referred to Chamelea, and the group
dates back to the Miocene epoch in Europe (V. cothurnie, Dujardin),
and to the Oligocene in the United States.

Salacia, Jukes-Browne, 1914. Type, Venus Jamellata, Lam.
Etym.: Salacia, the wife of Neptune.

Shell oblong or oval, flattened at the umbones, with distant, thin,
erect, or recurved concentric lamelle. Lunule small and lanceolate.
Escutcheon only defined in left valve. Median teeth always bifid.
Nymphs smooth. Margins feebly crenulate. Pallial sinus moderately
deep. Pedal scar long, narrowly confluent with adductor.

This group seems to be restricted to Australia and New Zealand.
It comprises Chione yatesi, Gray, and Ch. yacksoni, Smith, and perhaps
C. calophylla, which links it with Clausinella.

Bassina, J.-Br., 1914. Type, Venus paucilamellata, Sow. (= V. alata,
Xeeve). Dedicated to Lieut. Bass, after whom Bass’ Straits were
named.

Shell sub-trigonal, thick, convex, brownish, concentrically striated
with only a few erect scales on the anterior slope. Escutcheon not
defined. Both dorsal margins of the right valve grooved, and those
of the left bevelled to fit.

The only species known occurs along the south coast of Australia
and round Tasmania.

' It was by mistake that this species was referred to Circomphalus on p. 74.

JUKES-BROWNE: SYNOPSIS OF THE VENERID®. 82

Genus Protornaca, Dall, 1902.

Type, Chama thaca, Molina (= Venus dombeyi, d’Orb.).

This group of shells was separated by Dr. Dall in his ‘‘ Synopsis of
the Veneride ’’,’ und placed as a sub-genus of Zapes. I have protested
against this allocation on two previous occasions, holding that the
species which he took as his type, i.e. that usually known as Venus
dombeyi, is much more closely allied to Venus and Chione than to
Tapes. A careful examination of all the species which Dr. Dall then
included under the name Protothaca has convinced me that they do
not form a homogeneous natural group, but a heterogeneous assemblage.
One of the species belongs to the typical section of Chione, another is
an abnormal form of Zapes; but the rest (including the type) do
present peculiarities which distinguish them both from Chione and
Tapes, and possess characters which make it inconvenient to class
them as a sub-genus of either.

The fact is that Dr. Dall’s diagnosis only records some of the
differences between Protothaca and Chione, and those are chiefly
superficial differences. He dwells chiefly on the external sculpture,
and does not say a word about the disposition of the teeth, nor does
he sufficiently distinguish the group from Zapes. ‘The sculpture,
being partly concentric and partly radial, differs little from that
possessed by the typical section of Chione, and would not entitle the
shells to more than sectional value, but there are points of much
more importance, and one of these is the closer approximation of the
teeth. No doubt this was perceived by Dr. Dall, and was the chief
reason for his placing the shells under Zapes, although he does not
say so, nor does he distinguish Zapes from Chione by the divergence
of the teeth.

It is a fact, however, that in Protothaca both the posterior cardinals
are shorter than in Chione, the left posterior being a short oblique
tooth crossing the hinge-plate on a line nearly parallel to the hinder
side of the median, while i in Chione it is a long tooth, parallel to the
base of the ligament. Protothaca resembles Chione in having a strong
hinge-plate, and consequently there is a space between the left
posterior cardinal and the base of the ligament. The ligament itself
is very long, extending nearly to the end of the posterior dorsal slope,
the consequence being that the groove, which is usually found on this
margin of the right valve, is in Protothaca merely a short indentation
for the reception of an equally short projection on the left valve.
In this respect it differs from Chione, and resembles some forms of
Tapes, such as 7. decussatus and 7. pullastra.

The following is a list of the recent species which are referred to
Protothaca and its section Callithaca by Dr. Dall :—

Chione grata, Say (= Venus discors, Sow., and FV. histrionica,
Sow.).

Chama thaca, Molina (= Venus dombey?, ’Orb.).

Chione ruderata, Desh.

1 Proc. U.S. Nat. Mus., vol. xxvi, p. 364, 1902.

83 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

Ch. petiti, Desh. (as Savidomus; = Venus rigida, Gould, and
Tapes diversa, Sow.).

Ch. staminea, Conrad (= Venus mundulus, Reeve).

Tapes orbella, Carpenter.

T. laciniata, Carp.

T. tenerrima, Carp. (the type of Callithaca, Dall).

Of these eight species I consider the first to be a typical Chione, for
it has the teeth of Chione with the left posterior parallel to the
nymph, and it may be regarded as the Pacific analogue of the
Caribbean Ch. granulata, which Dr. Dall himself classes as a Chione.
The last species on the list is very different from all the others, and
I regard it as a form of Zapes. The remaining six species do form
a special group with characters of their own; they differ from Chione
in the features already mentioned, as well as in the greater depth of
the pallial sinus. The sub-genus of Zapes which they most nearly
resemble is Ruditapes (7. decussata), but from this they differ in the
following particulars, i.e. in having—

A stronger hinge-plate with a broader anterior expansion.
. Longer and stronger teeth.

. Smooth nymphs, never corrugated.

Left anterior tooth entire, not grooved.

Crenulated valve-margins.

Pedal scar confluent with adductor.

OQ om whe

The fact is that the Protothaca group has characters which make
it inconvenient to include it either under Venus or under Tapes, and
1 therefore propose to consider it a genus, especially as I believe the
following species may also be referred to it, Chione gedoensis, Lischke,
Ch. hiraset, Pilsbry, Ch. costata, Q. & G., and possibly the shell known
as Petricola elliptica, Sow. (from Peru). ‘The group is essentially
a Pacific one, and may be defined as follows :—

Sheil oblong, of dull white, yellow, or brownish colouring, sculpture
more or less cancellate, but the radial ribs often becoming dominant.
Lunule defined, but escutcheon absent, or only defined in the left
valve. Ligament very long and prominent. Hinge-plate strong and
deep; teeth separate and rather near together, both medians bifid,
and both posteriors more oblique than in Chione. Nymphs smooth.
Pallial sinus fairly deep and rounded in Californian species, short and
subangular in others. Pedal scar confluent at top with that of the
adductor. Ventral margin crenulated, but often becoming smooth
posteriorly. Ridge and groove on dorsal margins very short.

Dr. Dall describes the animal of the type as having short siphons
which are united to their tips, the foot hatchet-shaped (? linguiform),
and not byssiferous nor exhibiting even a byssal groove.

There is another shell which I am inclined to place under Protothaca
in spite of the fact that its margins are entirely smooth, and that it
was placed under ‘ Mareta’ by Dr. Dall. This is the Venus rufa,
Lam., a large, thick, oval shell which has a curiously eurved hinge-
plate and teeth, which are quite different from those of Samarangia.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ, 84

I propose to make it a sub-genus of Protothaca with the name of
Rhomalea, from pouadeos, strong. It can be defined thus :—

Sub-genus.

Rhomalea, J.-Br., 1914. Type, Venus rufa, Lamarck. Habitat,
Peru.

Shell similar to Protothaca, but nearly smooth; showing faint
radial striz all over the surface, obscured on the anterior side by
stronger concentric strie. Ligament very large and prominent.
Hinge-plate curved and both posterior teeth very short. Interior
margins smooth, pallial sinus sharply pointed. Pedal scar small and
separate from that of adductor. Venus kennerlyi may perhaps be
associated with rufa, as its dentition and sinus are similar.

Genus SamaranaiA, Dall, 1902.

Shell oval or sub-quadrate, concentrically striated or minutely
reticulated. Inner margins of valves smooth. Lunule flat, circum-
scribed. Escutcheon not defined. Hinge-plate short, with a flat or
concave anterior expansion. Teeth divergent, three in each valve,
the left anterior and median united at top, and fitting over the right
anterior; left posterior generally long and partly confluent with the
nymph. Pallial sinus fairly deep. Pedal scar more or less confluent
with that of the adductor.

Samarangia, 8.8. Type, Venus quadrangularis, Ad. & Rye.

Shell solid, sub-quadrate, dull white. Ligament long. Valve-
margins smooth. Pallial sinus horizontal, linguiform, and pointed.
Pedal scar oval, very narrowly confluent with that of adductor.
So far as my own knowledge goes, this section only includes
quadrangularis, lenticularis, Sow., and exalbida, Chem.

Sub-genera.

Mercimonia, Dall, 1902. Type, Venus bernayi, Cossmann (Eocene
fossil).

Shell sub-orbicular, substantial, convex, concentrically striated.
Lunule feebly defined, ligament sunk. Hinge-plate deep, and
anterior concavity well developed. Right posterior tooth widely
bifid, and both posteriors curved. Left median and anterior united
at top and both entire. Posterior marginal groove long. Ledal scar
confluent with that of adductor. Pallial sinus variable in depth and
shape.

A perusal of the description given by Messrs. Cossmann and
Peyrot of V. dyyardini of the Bordeaux Miocene, and the examination
of a left valve, for which I am indebted to Professor Peyrot, have
convinced me that it belongs to the same group as the Eocene shells
described by M. Cossmann and mentioned by me in a previous
volume of these Proceedings (vol. viii, p. 169).

Textivenus, Cossmann, 1886. Type, Venus texta, Lam. (Eocene).

Shell small, oval, ornamented with raised obliquely reticulate
strie. Valve-margins smooth. Only right posterior margin grooved.
Pallial sinus ascending. Pedal scar narrow, and confluent with that
of adductor.

85 PROCKEDINGS OF THE MALACOLOGICAL SOCIETY.

Genus Gomputina, Morch, 18538.

The isolation of Gomphina as a genus was discussed and maintained
by me in 1909,' and at the same time it was pointed out that the
small group of shells now known as Liocyma seemed to stand in the
relation of a sub-genus. Since then I have ventured to affiliate
the small American shells called Psephis by Carpenter in 1864, but
renamed Psephidia by Dr. Dall in 1902, and I have also described
a new sub-genus under the name of Acolus, based on a species from
the Falkland Islands which was referred to Psephis by Messrs. Preston
and Cooper in 1910.2 The species of Gomphina proper are only
found on the western side of the Pacific Ocean from Australia north-
ward to Japan, and the other groups are entirely American.

Generic characters: Shell trigonal or oval, solid, smooth or con-
centrically striated. Lunule flat, circumscribed. Escutcheon not
defined. Valve-margins smooth or tangentially grooved. Right
posterior and left anterior dorsal margins grooved to receive the
opposite bevelled margins. Hinge-plate short and triangular; teeth
equally divergent, and both medians generally grooved. Pallial
sinus small. Pedal scar separate from that of the adductor.

Gomphina, s.s. Type, Venus donacina, Chem.

Shell trigonal, smooth, and near equilateral. Three teeth in each
valve, the left posterior confluent with the nymph, and sometimes
rugose, as also the right nymph. Pallial sinus short and rounded.

Sub-genera.

Psephidia, Dall. Type, Psephis lordi, Baird.

Shell small, smooth, sub-equilateral. Left posterior tooth free
Inner margins tangentially grooved and microscopically crenulated.
Pallial sinus short, triangular.

Acolus, Jukes-Browne. Type, Psephis foveolata, Preston & Cooper.

Shell small, trigonal, equilateral. Teeth 8 in the left valve, 2 in
the right. Ventral margins smooth, but dorsal margins striated.
Pallial line very slightly inflected.

Liocyma, Dall. Type, Venus fluctuosa, Gould.

Shell oval, inequilateral, oblique, concentrically striated. Three
teeth in each valve. Pallial sinus short and rounded. Valve-margins
smooth.

Genus Crementia, Gray, 1842.

Animal having long siphons, united for their, whole length, with
plain orifices. Foot compressed and sub-quadrate (or hatchet-shaped)
like that of Dosinta. Mantle-margins plain.

Shell oval or oblong, convex, thin or substantial, sculpture
generally concentric and feeble, but sometimes reticulate. Lunule
indefinite or feebly defined. Escutcheon generally, depressed, but
not defined. Valve-margins smooth, and right posterior dorsal
margin grooved. Hinge-plate weak or strong in relation to the
thickness of the shell, with a concave expansion in front of the teeth ;

1 See Proc. Malac. Soc., vol. viii, p. 233.
* See Ann. Mag. Nat. Hist., vol. xii, p. 479, 1913.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ, 86

three divergent teeth in each valve, the right posterior being
generally bifid or composed of two lamine; the left posterior is
a short tooth crossing the hinge-plate. Pallial sinus variable.

Clementia, s.s. Type, Venus papyracea, Gray.

Shell thin, oval, concentrically undulated and striated. Hinge
weak, teeth separate, right posterior bifid or composed of two
compressed plates, median and anterior near together, left median
sometimes bifid. Pallial sinus generally subangular and ascending.
Pedal scar large, oval, and opening narrowly into that of the adductor.

Terentia, Jukes-Browne, 1914. Type, Clementia granifera, Sow.

Shell thin, oblong, very inequilateral, ornamented with irregular
divaricate or reticulate strie. No escutcheon. Hinge narrow, teeth
short, and anterior concavity small; all the teeth entire, the right
posterior being tall and narrow, the left very slight and feeble.
Pallial sinus very large and deep, and partly confluent with the
pallial line. Pedal scar large and confluent with that of adductor.

Sub-genera.

Flaventia, Jukes- Browne, 1908. Type, Venus ovalis, Sow.
(a Cretaceous fossil).

Shell elongate-oval, fairly strong, with a defined lunule. Teeth
all entire, except the right posterior, which is widely bifid, the
hinder lamina being much longer than the other; left median narrow
and oblique, anterior triangular. Pallial sinus deep, ascending and
rounded.

Psathura, Deshayes. Type, Venus fragilis, Lam. (an Eocene fossil).

Shell thin. Teeth small; right posterior bifid, median grooved ;
all in left valve entire. Pallial line without inflection.

Genus Cycrina, Deshayes, 1849.

Type, Venus sinensis, Gmelin.

Shell orbicular, convex, concentrically striated with subordinate
radial strie in the typical section. No defined lunule or escutcheon.
Hinge-plate well developed, with a short anterior and long posterior
extension, so that the teeth only occupy a small space. Both posterior
teeth are short, and traverse the plate obliquely. Right posterior and
sometimes left median bifid. Pallial sinus deep and ascending. Pedal
scar small and confluent with that of adductor.

Cychina, s.s. Valve-margins crenulated. Pallial sinus angular in
sinensis, but rounded in flavida, and subangular in orientalis.

Sub-genus.

Cyclinella, Dall, 1902. Type, Dosinia tenuis, Récluz.
Hinge-plate and teeth like that of Cyelina, but valve-margins smooth.
Pallial sinus sharply angular, ascending.

Genus Gemma, Deshayes, 1853.

As I have recently described this genus in the Annals and Magazine
of Natural History! and have given a corrected description of it with

1 Ser. VIII, vol. xii, p. 473, 1913.

87 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

reasons for regarding Parastarte as a sub-genus, I need only here
quote the definitions there printed. It is a small group of small
American shells which seems to stand by itself, though, by the
characters of the hinge and the crenulation of the margins, it
resembles Chione more than any other.

Shell small, oval or sub-trigonal, smooth or concentrically striated.
Lunule large, superficially defined. No escutcheon. Hinge-plate
short. Teeth widely divergent, the left posterior inconspicuous or
obsolete, but, when present, parallel to the nymph; left median and
right posterior bifid, all the rest entire. Right postero-dorsal and left
antero-dorsal margins grooved to receive ridges on the opposite margins.
Ventral margins finely crenulated.

Gemma, s.s. Type, Venus gemma, Totten.

Shell oval, striate. Three teeth in each valve. Marginal grooves
long and deep. Pallial sinus generally rounded, ascending.

Sub-genus.
Parastarte, Dall. Shell thick, smooth, equilateral, and sub-
trigonal. Three teeth in the right valve and only two in the left.
Marginal grooves narrow. Pallial line only slightly inflected.

Genus CyprimerrA, Conrad, 1864.

Fossil shells of Cretaceous age, and represented by one small species
in the Eocene of the Paris Basin.

Shell more or less orbieular, smooth or concentrically striated.
Umbones small. Lunule superficial and feebly defined. No escutcheon.
Hinge-plate prolonged anteriorly to form a concave space. Teeth
widely divergent, the right posterior being so broadly bifid that its
components form two separate teeth, while the median and anterior
are directed forward. Left median thick and sometimes bifid.

Cyprimeria, s.s. Type, Cytherea excavata, Morton.

Shell sub-orbicular, compressed. Left median tooth thick, triangular
and bifid; left posterior long and nearly parallel to the nymph. Pallial
line with a very slight inflection.

Cyclorisma, Dall, 1902. Type, C. carolinensis, Conrad.

Shell oval or sub-orbicular, convex. Left median tooth entire, left
posterior short and crossing the plate obliquely. Pallial sinus fairly
deep, ascending and subangular.

Genus Marcia, H. & A. Adams, 1857.

This genus and its separation from Tapes have been fully discussed
in a previous paper.' The name was proposed by the Messrs. Adams
in their Genera of Recent Mollusca in 1857 for a group of shells which
they regarded as a sub-genus of Chone. By Romer, however, these
species were included in his Hemztapes and Katelysia groups, the
former being regarded as a section of Zapes; and in 1887 Fischer
recognized Mareta, as well as Hemitapes and Katelysia, placing them

1 Proc. Malac. Soc., vol. viii, p. 233, 1909.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ. 88

all under Zapes. It was Dr. Dall in 1902 who first proposed to
separate this assemblage as a genus under the name of Marcia, but he
was mistaken in supposing that a type had been properly indicated,
so that it was not until 1909 that Venus pinguis was definitely
selected as its typical species, and that Samaranygia was excluded
from the genus. The following is an abstract of the generic definition
then given by me :—

Shell oval or oblong, inequilateral and oblique, smooth or con-
centrically striated. Lunule well defined, but escutcheon only
defined by absence of sculpture. Valve-margins smooth. Hinge-
plate short, with three fairly strong, divergent, and nearly equidistant
teeth; the right posterior and median, as well as the left median, are
bifid or grooved, and frequently all the teeth are rugose. The right
nymph and the left posterior tooth are striated with linear riblets ;
the posterior right and anterior left dorsal margins are grooved.
Pallial sinus of ‘moderate depth and rounded. Pedal scar separate
from that of the adductor.

Marcia, s.s. Type, Venus pinguis, Chem.

Shell oval or oblong, convex, smooth or obscurely waved, often
attenuated posteriorly. Lunule distinct and impressed. ‘Teeth rather
small and widely divergent, the left posterior rugose and confluent
with the nymph, left anterior and median both grooved.

This group includes V’. nebulosa, Chem., paupercula, Chem. (with
the varieties Kochi, Phil., ambigua, Desh., and kraussi, Desh.),
2? enterrupta, Koch., and fumigata, Sow. (= levigata, Sow.). It
inhabits the Indian Ocean from the east coast of Africa to Australia
and the Philippine Islands.

Sub-genera.

Hemitapes, Romer, 1864. Type, Venus rimularis, Lam.

Shell oval or sub-trigonal, convex, and generally tumid. Seulpture
of narrow irregular concentric ribs. ‘Teeth short, the left posterior
oblique and only in part adherent to the nymph; both the anterior
teeth are tall and entire. Pallial sinus fairly deep.

This group is also East Indian and Australian, including flammiculata,
Lam., striata, Chem., cor, Sow. (non Hanley), philippit, Desh.,
marmorata, Lam., variabilis, Phil. (with its varieties daterisulca,
Sow., orventalis, Desh., ustulata, Desh., and recens, Sow.), flammea,
Gmelin (= radiata, Chem.), and recens, Chem. (not Sow.).

Katelysia, Romer, 1857. Type, Venus scalarina, Lamarck.

Shell obliquely oval, compressed or convex, anterior side very
short; sculpture of strong concentric ridges which are sometimes
corrugated by radial ribs. Teeth nearly straight, but divergent, and
all more or less rugose. Pallial sinus small, obtuse, or rounded.

This is a small group of Australian shells comprising Venus strigosa,
Lam., V. corrugata, Lam., V. peronti, Lam., V. aphrodina, Lam., and
V. regularis, Desh. To these may, I think, be added the shell
described by Deshayes as Saxidomus decussatus and said to come from
South America, but of which I have specimens from Japan.

89 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY,

The genus Tapers.

Even after the separation of Marcia and its allies, the shells which
have been grouped under the head of Zapes form a heterogenous
assemblage which is difficult to define in terms that would be
applicable to all of them. If we neglect the variations in shape
and external sculpture, and confine our attention to the internal
characters, we find that the group typified by Zapes litteratus differs
considerably from that which was called Zeatrix by Romer, and still
more from the shell which is commonly known as Zapes pullastra,
which last is in many respects more closely allied to Venerupis than
to Tapes proper. So great is this resemblance that the cavicolar
variety of Z. pullastra was supposed to be a distinct species by
Lamarck, and was by him classed as a Venerupis under the name of
V. perforans.

After a careful examination of the two assemblages which have
gone under the names of Zupes and Venerupis I have come to the
conclusion that they really form a connected series with Tapes
litteratus at one end and Venerupis irus at the other; and further
that it is almost impossible to frame a definition of the one that
would exclude the other. Consequently I would either make one
genus of them under the name of Zapes with Venerupis as a sub-genus,
or divide the series into three genera which could then be more easily
defined and distinguished. On the whole, and having special regard
to the characters of the hinge, I prefer the latter arrangement, and
find it more convenient to create a new genus for the shells which
occupy an intermediate position between the two extremes.

Here, however, we are brought up against the thorny fence of
priority in the selection of a name and type for this intermediate
genus. The groups of which it can be formed are those for which
the following names have been proposed: Textrix, Paratapes, Pullastra,
Polititapes, Callistotapes, and Protapes. Of these, Pullastra is the
oldest, having been proposed by Sowerby in 1826, while the Zextrix
of Romer only dates from 1857, and was, moreover, preoccupied by
Sundeval in 1833, so that the next name was Paratapes (Stoliezka,
1871). Pullastra, however, can only be recognized as a subsidiary
group, whereas the type of Paratapes is the first species on Romer’s
list of Zextrix, so that the one name could stand for the other, and
could be defined so as to include the same species.

Under the International Rules, however, the oldest name in any
assemblage of groups must be taken as the generic name, and, if we
submit to this ruling, Pudlastra would be the name of the genus, and
Paratapes would have to rank as a sub-genus. ‘he only other way
out of the difficulty is to detach Pullastra from the intermediate
genus, and to consider it as a sub-genus of Venerupis. This indeed
[ regard as the most convenient and most natural arrangement of the
several groups, for Pullastra is intimately connected with Venerupis
through the species which were separated by the Messrs, Adams
under the name of Myrsus. Some of these species have since been
referred to ZYapes and some to Venerupis by different authors, but
they are best united under the head of Pullastra.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZA, 90

It must here be remarked that a genus Pullastra was first
proposed by Sowerby in 1826,’ and it included most of the species
which Megerle and Lamarck had respectively allotted to their genera
Tapes and Venerupis. One can only suppose that Sowerby was
ignorant of Megerle’s name, and did not agree with Lamarck’s
separation of Venerupis. Anyway, the name might have been
dropped as a synonym of Tapes if it had not been revived by
subsequent authors for a section of that genus. The Messrs, Adams
used it in 1857 for a group of species which did not include V. pullastra,
a group which was in the same year called Paratapes by Romer.
Under the International Rules a genus which contains a species
bearing the same name must take that species as a type; consequently
Fischer was right in giving Zuapes pullastra as the typical example
of his section Pullastra, and Dr. Dall was right in definitely
indicating that species as the type of a sub-genus Pullastra.

Lastly, with regard to the animals of the different forms of Zupes,
the differences which exist between them are not in very close
correlation with the differences of the shells, and would not lead
us to the same generic grouping. If, for instance, we were to group
them in genera according to the partial union or the total separation
of the siphons, we should get a different classification from that based
on the characters of the shells.

Thus Zapes litteratus has long and nearly equal siphons which are
entirely separate from one another. In Paratapes euglyptus, for
a specimen of which I am indebted to Mr. Hirase of Kyoto, the
siphons are also quite free and separate from one another, but in
Polititapes (both riomboides and letus) the siphons are united for
about half their length. Again, in Zapes decussatus, the type of
Amygdala, the siphons are free and separate, but in Zapes philippi-
narum (sent me by Mr. Hirase) they are united for three-quarters
of their length.

The differences in the foot also show the same want of correlation.
In 7. litteratus the foot is long and tongue-shaped, but does not
possess a byssus, nor even a byssal groove, so far as I could see in
the spirit-preserved specimens sent me by Mr. J. Banfield of Dunk
Island, Queensland. In Paratapes the foot is very large, thick,
and elongated, and there is no trace of a groove at its base,
while in P. rhomboides, and in the aureus group, the foot is rather
small, with a byssal groove, and castrensis is said to have a small
byssus. Zapes decussatus has a small byssus, while 7. philippi-
narum, or, at any rate, the specimen examined by me, has only
a groove; both have a broad lanceolate foot, not thick, but rather
compressed.

The distribution of these Tapesine genera at the present day is
interesting, for the restricted section of Zupes is essentially tropical,
being only found in the Indian Ocean and in the western Pacific from
Japan to the northern parts of Australia.

1 Genera of Shells, Zool. Journ., vol. iii, p. 134.

91 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

Amygdala has a wider range, extending from the west coast of
Europe through the Mediterranean and the Indian Ocean to the
Philippines, Australia, and New Zealand. Callithaca is the only
American representative.

The typical section of Paratapes, again, is Indo-Pacific, the type
being quoted from Natal, India, Tasmania, but Polititapes is
restricted to the Mediterranean and the western coasts of the |
Old World.

It has been supposed that the name Amygdala could not be used
for a mollusc because it was preoccupied for an Echinoderm. This
idea was based on a statement of Agassiz, who referred to ‘‘ Amygdala,
Van Phelsum, 1774”, but Mr. Sherborn found that this was a mistake,
and that the name did not occur in Van Phelsum’s work on Echino-
derms (see Index Animalium, p. 46). Neither can the name be
rejected on account of the Amygdalum of Megerle (1811); con-
sequently it can be accepted from Rémer (1857), and since his first
species was Tapes decussatus, and this has been givenin textbooks as
the typical example of Amygdala, that species should be regarded
as the type.

The several groups above-mentioned are distributed in the three
genera Tapes, Paratapes, and Venerupis as follows.

Genus Tarrs, Megerle, 1811.

Shell oblong, inequilateral, and generally expanded posteriorly ;
concentrically striated or radiately ribbed. Lunule defined, but
escutcheon often obscure. Ligament long and prominent. Hinge
with three divergent teeth in each valve, only three of the six being
bifid; the left posterior directed backward so as to be nearly parallel
to the nymph. Valve-margins smooth. Pallial sinus fairly deep,
horizontal, and rounded.

Tapes, s.s. Type, Venus litterata, Linn.

Shell rather compressed, with small flattish umbones, concentrically -
striated or grooved. Escutcheon defined, but narrow. Left median
tooth broad, triangular, and deeply bifid. Pedal scar separate from
adductor.

Besides the varieties of 7. litteratus this group includes 7. turgida,
Lam., 7. sulcaria, Lam., 7. deshayest, Hanley, 7. simelis, Desh., and
T. phenax, Pilsbry.

Sub-genera.

Amygdala, Romer, 1857. Synonym: &uditapes, Chiamenti, 1900.

Shell convex, bearing radiate ribs which are more or less decussated
by concentric ridges. Escutcheon not defined. Hinge-plate narrow
and curtailed behind, so that the posterior teeth are both very short.
Pallial sinus deep. Pedal scar small and narrowly confluent with
that of the adductor.

This group includes Zapes indicus, Sow., Z. variegatus, Sow.,
7. philippinarum, Ad. & Rve., 7. bruguiert, Hanley, and 7’ intermedia,

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ®. 92

Callithaca, Dall, 1900. Type, Zapes tenerrima, Carpenter.

Shell broadly oblong, sculptured, with fine radial riblets, crossed
by distant concentric ridges. Hinge-plate long with a space in front
of the teeth. Dorsal margins not grooved; ventral margin feebly
erenulated when young, but smooth in adult. Pallial sinus very
long and turned up at the end. Pedal scar elongate, separate, with
a connecting canal.

This species appears to stand by itself, and its dentition is very
different from that of Protothaca, with which Dr. Dall placed it.

Genus Pararapss, Stoliczka, 1871.

Synonyms: Pullastra, Adams; TZextriz, Romer, 1857 (not of
Sundeval); Hutapes, Chiamenti, 1900; Paphia, Dall after Bolten,
1902; Protapes, Dall, 1902.

Shell smooth or concentrically ribbed; generally coloured with
a glistening brownish periostracum. Lunule defined, but not the
escutcheon. Hinge-plate narrow, teeth short, near together, slightly
divergent, and of nearly equal length. Right dorsal margin grooved.
Pallial sinus moderate and rounded. Pedal scar always separate from
that of adductor.

Paratapes, s.s. Type, Venus textilis, Linn. (= textus, Chem.).

Shell oblong-elongate. ‘Two of the teeth in each valve bifid or
grooved, and the posteriors curved. Pallial sinus obtuse and ascending.

This section includes undulatus, Born, rotundatus, Linn., sulcosus,
Sow., amabilis, Phil., semirugatus, Phil., politus, Sow., graffec, Dunker,
schnellianus, Dunker, inflatus, Desh., meroeformis, Sow., liratus, Phil.,
euglyptus, Phil., malabaricus, Chem., and declivis, Sow.

Polititapes, Chiamenti, February, 1900. Type, Venus aurea, Gmelin.

Synonym: Callistotapes, Sacco, April, 1900 (type, Zapes vetulus).

Shell oval or oblong, concentrically grooved, with sometimes obscure
radial striation. Pallial sinus nearly horizontal.

This is a small group of European and West African shells which
seems to take the place of Paratapes in those regions. There are
a number of. Mediterranean forms which some regard as varieties
of aureus, but letus, Poli, texturatus, Lam. ( = petalina), and
castrensis, Desh., seem good species. Other species are rhombovdes,
Penn. (=virgineus, auctorum), British, and durus, Sow., from West
Africa. It has fossil representatives in the Miocene and Pliocene
deposits.

Genus Venerupis, Lamarck, 1818.

Type, Venus irus, Linneus.

Shell oblong, often irregular from its nesting habit. Sculpture of
radial lines or riblets, crossed by concentric ridges or striz. Lunule
indefinite. Escutcheon not defined, or only on left valve. Huinge-
plate very short and narrow, excavated and curtailed posteriorly, so
that all the teeth are very short, near together, and nearly parallel
to one another. Two of them in each valve are bifid or grooved,
but the teeth are often irregular and malformed. Groove on the
posterior dorsal margin obsolete. Ventral margin smooth. Pedal
scar separate from adductor.

93 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY.

Venerupis, s.s. Type as above. Shell with radial riblets crossed
by distant concentric ridges. Escutcheon defined by a ridge in the
left valve. Pallial sinus generally short, subangular, and ascending.

Claudiconcha, Fischer, 1887. Type, V. monstrosa, Chem.

Shell very irregular and inequivalve, the posterior margin of the
right valve so-expanded as to overlap that of the left. Escutcheon
not defined. Pallial sinus variable.

The typical section of Venerupis includes V. elegans, Desh., V. exotica,
Lam., V. lamellifera, Conrad, V. crenata, Lam., V. carditoides, Lam.,
V. planicosta, Desh., V. mitis, Desh., V. puleherrima, Desh., and
possibly V. diemenensis, Q. & G.

Claudiconcha includes V. eumingt, Desh., and V. madreporica, Jonas.

Sub-genus.

Pullastra, Sowerby, 1826. Type, Venus pullastra, Mont.

Shell with shallow radial or corrugated concentric sculpture.
Escutcheon not defined. Pallial sinus large and deep, sometimes
touching the pallial line below. Pedal scar separate.

The other species are P. geographica, Lam., P. fubagella, Desh.,
P. galactites, Lam., P. corrugata, Chem., P. cumingi, Sow., P. disrupta,
Sow., and ? P. dactyloides. I see no reason for separating the four
last as a distinct section under the name of Myrsus (Adams); some
specimens of P. pullastra are nearly as rough as corrugata, and the
pallial sinus varies both in depth and width. Moreover, two species
generally assigned to Venerupis, viz. V. rugosa and V. siliqua, have
a deep rounded pallial sinus, and are better placed under Pudlastra
than under Venerupis.

Genus Baropa, Stoliczka, 1871.

The separation of this genus from Zapes was advocated by me in
1908,' and at the same time I pointed out the close resemblance
between the hinges of Baroda and Venerella, the former being
a Cretaceous fossil and the latter being small oval shells found in the
Eocene of the Paris Basin. I see no reason to alter the opinion then
formed, because the similarity of the dentition is to my mind of more
importance than the dissimilarity of shape; but those who think
otherwise will doubtless agree with M. Cossmann in placing Veneredla
near DMercimonia.- On my view the following is a comprehensive
generic description.

Shell oblong or oval, concentrically striated, and sometimes also
radiately ribbed. Lunule superficial. Escutcheon not defined. Hinge
with three entire teeth in each valve, even the right posterior being
entire and very narrow. In the right valve the anterior and median
are placed under the umbo and directed forward, while the posterior
is directed backward, so that there is a wide space between it and the
median with an excavated border. In the left valve the teeth are
more equally divergent, and the plate is excavated between each of
them. Valve-margins smooth.

1 Proc. Malac. Soc., vol. viii, p. 171.

JUKES-BROWNE: SYNOPSIS OF THE VENERIDZ. 94

Baroda, s.s. Type, Venus fragilis, d’Orbigny.

Shell oblong and much elongated posteriorly. Sculpture concentric
only. Pallial sinus ample, horizontal, and rounded. Posterior teeth
very long and parallel to the nymphs.

Leanotia, Stoliczka, 1871. Type, Psammobia impar, Zittel.

Shell similar to Baroda, but having well-marked radial sculpture.

Sub-genus.

Venerella, Cossmann, 1886. Type, Venus hermonvillensis, Desh.

Shell small, oval, short, concentrically striated. Hinge as above.
Pallial sinus fairly deep, ascending, rounded. Pedal scar small, but
apparently confluent with that of the adductor.

In the preparation of this account of the Veneride I have received
much valuable assistance from Mr. J. C. Melvill and Mr. J. J.
MacAndrew, who have most kindly lent me specimens in their
collections for examination, and also from Mr. E. A. Smith, to whom
I am indebted for much information, not only about shells in the
British Museum but about matters which required reference to various
publications. I have also to thank Mons. M. Cossmann, of Paris,
and Professor Peyrot, of Bordeaux, for specimens of Eocene and
Miocene species, and for information respecting other species from
those formations.

Stephen Austin and Sons, Ltd., Printers, Hertford.

_ «

Walacological Soctety of London.

(Founded 27th February, 1893.)

Officers and Council—elected 18th February, 1914.
President :—Rev. A. H. Cooks, M.A., D.Sc., F.Z.S.

Vice-Presidents :—A. 8. KEnNARD, F.G.S.; R. BuLien NrEwrTon, F.G.S.;
H. B. Preston, F.Z.S. ; E. R. SYKES, B.A., F.L.S.

Treasurer :—J. H. Ponsonsy, I°.Z.8., 15 Chesham Place, London, S.W.

Secretary :—G. K. Gupu, F.Z.S., 9 Wimbledon Park Road, Wandsworth,
London, S.W.

Editor :—E. A. Surrn, [.8.0., 22 Heathfield Road, Acton, London, W.

Other Members of Council:—G. C. Crick, F.G.S.; T. Irnepare; C.
OtpHaM ; G. C. Rosson, B.A. ; J. R. pe B. Tomutn, M.A., F.E.S. ;
B. B. Woopwarp, F.L.S.

By kind permission of the Council of the Linnean Sociwry, the
MEETINGS are held in their apartments at Bortinaron Hovusp,
Piccapiniy, W., on the second Frma¥in each month from NovEMBER
to JUNE.

The OBJECT of the Society is to promote the study of the Mollusca,
both recent and fossil.

MEMBERS, both Ordinary and Corresponding (the latter resident
without the British Islands), are elected by ballot on a certificate of
recommendation signed by two or more Members.

LADIES are eligible for election.

The SUBSCRIPTION is, for Ordinary Members 10s. 6d. per annum
or £7 7s. for Life, for Corresponding Members 7s. 6d. per aunum or
£5 5s. for Life. All Members on election pay an Entrance Fee of 10s. 6d.

The PROCEEDINGS are issued three times a year, and each
Member is entitled to receive a copy of those numbers issued during
membership.

[ Vols. I-VIII and Vol. IX, Parts I-III, consisting of 52 Parts,
price 5s. net per Part. Parts 1V-VI of Vol. IX, and all
succeeding Parts, price 7s. 6d. each. A discount of 20 per
cent upon the above prices is allowed to Members purchasing
these Volumes or Parts through the Secretary. ]

Further information, with forms of proposal for Membership, may be
obtained from the Secretary, to whom all communications should be sent

at his private address, as given above.

Jukes-Browne, Alfred John
430 _ A synopsis of the family
Veneridae .

(Fil .

PLEAS T REMOVE

OR SLIPS FROM THIS POCKET

UNIVERSITY OF TORONTO LIBRARY

1 400 €0 eb 10 LL 6€
4. Wall SOd S1HS AVG JONVY CG

M3IASNMOG LV 1.LN