40 
SHELL GALLERY. 
Cases 179 
181. 
Cases 183- 
185. 
Cases 192- 
194. 
Oysters. Still more remarkable is Miilleria lobata of Colombia, which, 
when young, freely moves about and has two adductor muscles, but 
in time becomes attached and stationary, and then possesses but a 
single adductor. 
The Tellinas have usually thin shells, and their two siphons are 
longer and more completely separated from each other than in the 
Veneridm. The pallial line is widely and deeply sinuated, and the 
ligament generally external. In the genus Semele of the family 
Scrobiculariidoz, it is placed within the hinge-margin. They live 
in great numbers beneath the sand in shallow water, and are 
occasionally used as food. 
The Madrid®, have an internal ligament to the hinge, the 
siphons are joined together and fringed at the ends, and the pallial 
line is more or less sinuated. Spisida solidissima (Case 184), the 
largest species found on the coast of the United States, is a common 
article of diet. 
The next family, Veneridw, have long respiratory siphons and 
a sinuated pallial line. Many of this tribe are very beautiful in 
form and colouring, and most of them have very hard strong shells. 
The valves are united above by an external ligament, and the hinge- 
plate is toothed. Nearly all of them live buried an inch or two 
beneath the sand or mud, but a few are 
found burrowing in rocks. Probably the 
majority of the species of this family 
might be used as food. Venus verrucosa, 
of our own southern shores, is frequently 
eaten both in this country and abroad ; and 
Venus mercenaria (Case 189) is commonly 
sold in the markets of Philadelphia and 
New York. Cytherea lusoria (Case 185) 
also forms a favourite article of diet among 
the poorer classes in Japan, and several 
kinds are eaten by the natives of New 
Zealand and other countries. 
Some of the "Cockles" (Cardiida) 
from warm latitudes are highly coloured 
and adorned with most beautiful sculpture. 
Probably the majority are eatable, as 
the common cockle (Cardium edule) of the 
British coast. The foot of these molluscs is very large, bent, and 
used for leaping. The siphons are short and fringed at the margins. 
Common British Cockle 
(Cardium edule). 
, foot ; b, exhalant siphon ; 
c, branchial or inhalant 
siphon ; d, edge of mantle; 
e, ligament; /, umbones 
or beaks of the shell. 
