CONCHIFERA OR BIVALVES, 



49 



peaked at the apex, generally 

 open at the base, rather acute, 

 somewhat gaping. The valves 

 are destitute of a hinge, being 

 supported by their muscular ad- 

 hesion. Animal having two long 

 ciliated arms, curled up during 

 repose. — 3 recent and 1 fossil 

 species. 



Mr. Cumming met with con- 

 siderable numbers of these shells in the Philip- 

 pine Islands : their inhabitants are often eaten 

 by the natives, but he does not think them 

 wholesome. They live buried in hard sand, and 

 can only be found at low water. 



2. Terebratula. — Shell inequivalve, equi- 

 lateral, oval or orbicular, adhering 

 by a short gelatinous tendon. The 

 upper valve has the apex often 

 curved inwards, and perforated for 

 the passage of the tendon. It has 

 also a single tooth-like process on 

 each side. The lower valve has 

 two slender shelly processes, generally recurved 

 and bent. Animal having a ciliated appendage 

 E 



