73;5 



and more flattened towards the ventral margin; in this species 

 they become more numerous and close, but lose none of their 

 sharpness ; the outline of the anterior side in this species is more 

 hollowed out at the lunule, wliich is rather excavated and dark 

 brown. 



China. In Mr. Cuming's collection. 



89. Venus pr^parea (pi. clxi. f. 200), Say, An. Sc. Nat. 

 vol. ii. p. 271. V. calcarea, Thilippi, Abbild. Venus, t. 3. f. 1. 

 Y. Mortoni, Conrad ? 



" V. testa ovato-orbiculari, alba, opaca, veluti calcarea, cingulis 

 transversis lamellosis parum elevatis distautibus demum evanescen- 

 tibus sculpta ; area lanceolata, planata, laevi ; lunula cordata, linea 

 profunda cincta, compressa, striata ; margine subintegerrimo." 



Of an ovate, rather compressed form, of a greyish or chalky 

 whiteness, the back rather truncated; in the upper half of the 

 shell the concentric laminae are distant, entire, and sharply lami- 

 nated, but near the margin, in the centre, are pressed down and 

 broad. 



North America. 



90. Venus tenuilamellata (pi. clxi. f. 195), So2verbi/,jiin. 



V. testa alba, ovali, subventricosa, lameDis tenuibus erectis dis- 

 tautibus Bequahbus cincta; latere antico brevi, margine superiore 

 et lunula excavatis; umbonibus promiuulis; latere postico ob- 

 longo, subtruncato; margine dorsali simpHci, depresso; margine 

 ventrali intus Isevigato. 



Tliis shell is quite distinct from V. Mortoni, which it resembles 

 in general appearance; it has the concentric laminae equal and 

 equidistant throughout, and the inner margin smooth. Only one 

 specimen has been found. 



Valparaiso; dredged by Mr. Cuming in sandy mud at twenty 

 fathoms. 



91. Venus mercenaria (pi. clxii. f. 204, 205, 206), Lin- 

 naus, Syst. Nat. 12th edit. p. 1131. Test. jun. V. notata. Say, 

 Journ. An. Nat. Sc. Phil. vol. vi. p. 271. V. obliqua et V. cy- 

 prinoides, Anton. 



V. testa cordata, ovata, crassa, obliqua, prope umbones et ad 

 latera striis elevatis concentricis suba;quaHbus distautibus cincta, 

 in medio plana, eetate ferruginea, concolore, intus postice violacea ; 

 test. jun. albida, fusco-maculata, postice fusca, intus alba, latere 



