40 



SHELL GALLEEY. 



Cases 179- 

 181. 



Cases 183- 

 185. 



Cases 185- 

 192. 



Cases 192- 

 194. 



Oysters. Still more remarkable is Mulleria lolata 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 

 many other Bivalves. The pallial line is widely and deeply siuuated, 

 and the ligament generally external. In the genus Semele of the 

 family ScrohicidariidcB, 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 Madridm 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 siuuated. Spisula solidissima (Case 184), the 

 largest species found on the coast of the United States, is a common 

 article of diet. 



The next family, Veneridce, 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 

 Vem/s mercenaria (Case 189) is commonly 

 sold in the markets of Philadelphia and 

 New York. Meretrix 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 " {Gardiidce) 

 from warm latitudes are highly coloured 

 and adorned with most beautiful sculpture. 

 Probably the majority are edible, like 

 the common cockle {Gardimn 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 Cock]e 

 (Cardium edule). 

 a, foot ; h, exhalant siphon ; 

 c, branchial or inhalant 

 siphon ; d, edge of mantle; 

 e, ligament; /, umbones 

 or beaks of the shell. 



