448 MARINE INVERTEBRATES 



of comestible species. Several of its genera have been named 

 after various goddesses and nymphs on account of the great 

 beauty of their shells. But from a purely biological point of 

 view also the Veneridce have claims to distinction, for they seem 

 to represent about the highest type of shell-development among 

 the bivalves. The test is extremely hard and often porcelanous. 

 It is solid without being ponderous and unwieldy in the sense of 

 causing the animal to be helplessly overburdened by the sheer 

 weight of its shell. The valves are equal and have three 

 stout cardinal teeth. The foot is strong, the animal is active, 

 the siphons are free or partially united, and the gills are more or 

 less crumpled and folded. There is a compactness and Well-regu- 

 lated arrangement of the organs in the Veneridce, which impress 

 one who has examined the anatomy of many pelecypods much 

 as a well-built, efficient, and space-economizing machine would 

 impress a mechanic. None of the organs are weak or crowded 

 out to furnish room for the undue or awkward development of 

 other organs. A good balance is preserved between them all, 

 the result being a high type of pelecypod. 



If we do not expect to find any of the more remarkable forms 

 of the VeneridcB upon our shores we shall be the less disappointed 

 when returning from collecting-expeditions. Nevertheless, there 

 are a few species of Cytherea, Dosinia, and Tivela in North Ameri- 

 can waters which are very handsome shells ; but those of our 

 species which are included under the generic name Venus are in 

 point of beauty not worthy of their promising name. 



F. mercenaria. This is the common " hard-shell clam," the " Lit- 

 tle Neck " of the hotels and restaurants, with which every one in New York 

 and New England is familiar. The species ranges from Cape Cod to 

 Florida, and occupies two different kinds of station : one in shallow 

 muddy bays near low-tide mark, in estuaries, etc. ; the other the sandy 

 stations in open deeper bays or the open ocean. Those coming from 

 " outside " have thinner, more delicate shells, with thin, concentric ribs. 

 They burrow in the sand or mud, or crawl quite rapidly. The siphons 

 are short and are united almost to their ends. The mantle is open (save 

 for the siphons), and the edges are delicately frilled. In the United 

 States this species is very extensively gathered for the markets. When 

 the oyster season closes in April, the hard-shell clam comes into vogue, 

 the season lasting until September or October. The clams are exten- 



