NOTES ON CUM-CULTURE. 



Owing to tlie importauce of several species of clams as food for man 

 and as bait in the line fisheries, it is deemed desirable to append a 

 few facts relating' to them and to their culture. 



Two species are in common use upon the Atlantic coast, one of them 

 also being an introduced species upon the Pacific coast. The quahog, 

 hard clam or round clam {Mercenaria mercenaria), is perhaps the more 

 important. It is the "clam" of the marliets of ISfew York, Philadel- 

 phia, and southward, and it is also utilized to some extent in New 

 England. It is a heavy-shelled form living on the muddy bottoms, 

 principally below low-water mark, where it is taken by meaiis of rakes 

 or by the process of " treading out," the clammer wading about and 

 feeling for the clams with his toes and then picking them up by hand 

 or with a short rake. 



The long clam or mananose {My a arenaria) is the principal species in 

 the markets north of Xew York, and, on account of the comparative 

 lightness of its shell, is often called the "soft" clam. This species was 

 introduced on the Pacific coast with oysters brought from the Bast, 

 and has now become widely distributed there and an important food 

 product. It is found principally on sandy shores or in a mixture of sand 

 and mud, between tide marks. Its long siphons permit it to burrow 

 to a considerable depth, and it is dug from its burrows by means of 

 spades, stout forks, or heavy hoes or rakes. 



The soft clam appears to be the only species which has been the 

 object of attempred cultivation, although no doubt the quahog is 

 equally favorable for the experiment. 



In Chesapeake Bay the soft- shell clam spawns from about September 

 10 to October 20. The eggs are of about the same size as those of the 

 oyster, and iu their early development pass through practically the 

 same stages. At the end of the free-swimming stage the clam is still 

 very small. It settles to the bottom, but instead of becoming attached 

 to shells or other firm bodies in the water it soon burrows into the bot- 

 tom until it is completely hidden with the exception of the tips of the 

 siphons, through which it derives its supply of food and oxygen from 

 the currents of Avater induced by the action of cells provided with hair- 

 like processes (cilia). Upon very soft bottom the young clam, like the 

 young oyster, is liable to become suffocated in the mud, but as it grows 



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