CONCHIFERA. 473 
The shells of this tribe are remarkable for the elegance of 
their forms and colours; they are frequently ornamented with 
cheyron-shaped lines. Their texture is yery hard, all traces of 
structure being usually obliterated. The Veneride appeared first 
in the Oobtie period, and have attained their greatest develop- 
ment at the present time; they are found in all seas, but most 
abundanciy in the trevics. 
VENUS, L. 
Synonyms, Merceneria, Antigone, and Anomalocardia (flexuosa) 
Schum, Chione, Megerle (not Scop.). Erycina (carioides), 
Lamarck, 1818. 
types ..paphia, li. Pl. XX., Fig. 7. 
Shell thick, ovate, smooth, sulcated, or cancellated ; margins 
minutely crenulated; cardinal teeth 3—3; pallial sinus small, 
angular; ligament prominent; lunule distinct. 
Animal with mantle-margins fringed ; siphons unequal, more 
or less separate; branchial orifice sometimes doubly fringed, 
the outer pinnate; anal orifice with a simple fringe and 
tubular valve; foot tongue-shaped; palpi small, lanceolate. 
V. textilis, and other elongated species, have a deep pallial 
sinus; V. gemma (Totten) has a very deep angular sinus, like 
Artemis; V. reticulata has bifid teeth, like Tapes; V. tridac- 
noides, a fossil of the United States, has massive valves, ribbed 
like the clam-shell. The North American Indians used to 
make coinage (wampum) of the sea-worn fragments of Venus 
mercenaria, by perforating and stringing them on leather 
thongs. 
Distribution, 176 species. World-wide. Low water—140 
fathoms. V. astartoides, Behrings’ Sea. V. verrucosa, Britain, 
Mediterranean, Senegal, Cape, Red Sea: Australia ? 
Fossil, 200 species. Oolites—. Patagonia, United States, 
Europe, India. 
? Volupia rugosa. (Defrance, 1829.) Shell minute, Isocardia- 
shaped, concentrically ribbed, with a large lunule. ocene, 
Hauteville. 
Saxidomus (Nuttall), Conrad. Oval, solid, with tumid um- 
bones; lunule 0; teeth 3—4, unequal, the- central bifid; 
pallial sinus large. 
Distribution, 8 species. India, Australia, West America. 
CYTHEREA, Lam. 
Bhymolog y, Cytherea, from Cythera, an Agean island. 
