CONCHIFERA OR BIVALVES. 89 



One of the muscular impressions is divided into 

 two; ligament external. Animal like the 

 other genera of this family. — 4 recent, and 12 

 fossil. 



Some of the species are English, and are 

 generally found on the sandy mud at very 

 variable depths. 



48. Cytheria. — Shell equivalve, inequi- 

 lateral, triangular or transverse, 

 ligament on the longest side, 

 four cardinal teeth in one valve, 

 and three in the other, lateral 

 teeth none. Animal, foot large. 

 — 78 species recent, and 9 fossil. 



These shells resemble much the Venus in their 

 beauty and colouring, but the number of teeth 

 slightly distinguishes them. They inhabit 

 the Indian and Atlantic Oceans, and one species, 

 the Cytheria lusoria, is found in the Chinese 

 seas; the latter is employed by the Japanese 

 and Chinese in certain games, and is painted 

 by them in the interior of various colours, and 

 representing various figures. 



This genus resembles so greatly the next 

 that some authors class them together: the 



