58 



CONCHIFERA. 



pallial sinus very large ; ligament on shorter side 

 of shell, sometimes internal. Animal with the 

 mantle widely open in front, its margins fringed ; 

 foot compressed, tongue-shaped ; siphons separate, 

 generally very long and slender ; palps large, trian- 

 gular. Burrowers in sand. 



Donax (Linn.). Wedge-shell. Shell three-sided, 

 wedge-shaped, closed ; the front produced, rounded ; 

 hinder side short, straight ; the edges notched ; 

 teeth t? f' i Animal with short siphons ; foot very 

 large, pointed ; palps small. 



D. anatinus. Fig. 79 ; J n. s. 

 politus. 

 trunculus. 



Ervilia (Turton). Shell minute, oval; right 

 valve with one prominent tooth in front, and an 

 obscure one behind ; left with two obscure teeth ; 

 no laterals. 



E. castanea. Fig. 80 ; n. s. 



Scrobicularia (Schumacher). Shell oval, nearly 

 equal-sided ; hinge-teeth small, i or f ; no laterals. 



