MOLLUSCA OR UNIVALVES. 153 



tectum sinense. Several species have the apex 

 rather spiral. They are found in the seas of 

 Europe, New Holland, &c* 



26. Hipponyx (Defrance).— obliquely 

 cap-shaped, and sometimes, perhaps generally, 

 supported on a solid shelly plate ; the shell and 



plate exhibit two strong muscular impressions, 

 which are in the form of a horse-shoe. Animal, 

 similar to Pileopsis. — 9 species, recent and 

 fossil. 



These animals do not always form a plate ; 

 indeed, they are as often found without the sup- 



* Mr. Cuming has lately found at the island of Zebu, 

 ! one of the Philippines, several specimens of Calyptrcea 

 equestris on masses of dead coral about low water mark, 

 having a testaceous plate attached to the mass to which 

 the true shell adheres. The edges are finely crenulated, 

 and turned up all round like a platter, as if to protect the 

 margin of the cap-shaped shell which rests within it. — 

 Reeve's Cow. Sys. J 



