712 



A large, thick, cancellated shell, the reflected concentric ribs 

 of which become less and less distant towards the ventral margin. 

 The V. leucodon has the same character of ribs, the same broad, 

 flat, excavated dorsal area, the same obliquely cordate form, and 

 only differs in having the hinder part of the shell of a dark colour, 

 and a dark rim continued round the inner margin around and 

 between the white deuticulations. 



Found in coarse sand at low w:ater, in the Gulf of California. 

 Cuming. 



25. Yenus callosa (pi. cliv. f. 44, 55), Conrad, Journ. Ac. 

 Nat. Sc. vol. vii. p. 252. 



V. testa ponderosa, oblique cordata, subovali, ventricosa, alba, 

 grisescente, postice fusca, intus postice purpurea ; costellis ra- 

 diantibus striatis planulatis et costellis concentricis interruptis ir- 

 regulariter squamosis antice et medio decussata, postice planata, 

 prope marginem divaricatim striata; latere postico subrostrato; 

 margine dorsali declivi, paululum depresso; latere antico brevi, 

 rotundato; lunula vix distincta; margine ventrali rotundato, 

 prope angulum posticum paululum emargiuato. 



This very thick, obliquely heart-shaped shell is remarkable for 

 the flattened scale-like nodules, formed by the crossing of the flat- 

 tish radiating ribs and the concentric layers. 



Sandwich Islands, and California. 



26. Yenus fluctieraga (pi. cliv. f. 42, 43), Sowerhi/,jun. 



Y. testa ponderosa, subobliquc rotundata, alba, concentrice pur- 

 pureo distanter fasciata, costelUs radiantibus postice et antice ma- 

 joribus et costellis interruptim fluctuatis intersecta; latere pos- 

 tico subangulatoj margine dorsali rotundato, subarcuato, maculato, 

 paululum depresso ; margine ventrali intus crenulato, purpureo. 



Named as above from the character of the concentric ridges, 

 which are fluctuated and as it were broken up on the surface; 

 the shell is soHd, rounded, and nearly white, with several bands of 

 livid colour; the inside is purple at the border, and about the 

 posterior impressions: altogether not unlike V. callosa, but rounder. 



Australia. 



27. Yenus granulata (pi. civ. f. 47, 48, 49), Gmel. n. 33. 

 Yenus violacea, Gmel. 34 ? Yenus "marica spuria," Chemn. Conch, 

 vol. vi. t. 30. f. 313. Y. entobapta, Jonas, in Menke, Zeitsch. fiir 

 Malac. 1845, p. 63. 



