76 



POPULAR CONCHOLOGY. 



This genus is found in the sand on the shores 

 of New Holland and the Mediterranean. 



30. Ungulina. — Shell transverse or almost 

 round ; valves nearly equi- 

 lateral, and not gaping; 

 one bifid cardinal tooth in 

 each valve, and at the side 

 a long pit ; no lateral teeth. 

 Animal unknown. — 2 species, recent. 



The exterior of this shell is rayed, and the 

 interior of a reddish colour ; it is found in Se- 

 negal, New Holland, and the Mediterranean, 

 and the animal perforates rocks, &c. The 

 shells are small, thin, and transparent. 



31. Amphidesma. — Shell round, or rather 

 oblong, slightly gaping and 

 inequilateral ; two cardinal 

 teeth and a long narrow pit 

 between, often lateral teeth; 

 ligament both external and 

 internal. Animal un- 

 known. — 16 species, recent. 



These shells, which are small, are found in 

 the sand on the sea-coasts of tropical countries, 

 and also those of England, Holland, &c. 



