98 



THE ECONOMIC MOLLUSCA OF ACADIA. 



Jones. Prince Edward Island, common and lar^e, Dawson. 

 Abundant on every sand bar, J. H. Duvar. Undoubtedly- 

 one of the most common of Molluscs around the entire coast 

 of Acadia. 





5i pfi oas 



Habits. No reader of this paper can require a description of tliis 

 species to enable him to identifj^ the Clam. Who does not know 

 this most ubiquitous of Molluscs? But not so many, perhaps, have 

 acquaintance with its habits. 



Upon every mud or sand beach 

 around the sea-coast of Acadia, the 

 visitor will see very many round holes, 

 half an inch in diameter, from which, 

 as he walks near them, streams of water 

 are frequently forcibly ejected. At the 

 bottoms of these, at a depth of from six 

 inches to over a foot, according to 

 locality and character of the soil, the 

 Clams are to be found, standing up- 

 right at the bottoms of their burrows, for 

 such they are. Yet it does not properly 

 stand upright in the sense that a man 

 does, for it stands head downwards, the 

 tough, black, protruding part, common- 

 ly called the head, not being that organ 

 at all. If this black part be dissected, 

 it will be found to consist of two tubes, 

 the " siphons," bound together, with 

 thick, tou^h walls, both leading into 

 the general cavity of the animal in which 

 all of the internal organs lie. The only 

 other opening into the animal's body is 

 a small one at the opposite end which 

 alloAvs the animal to thrust out its 

 muscular, extensible " foot." It is by 

 the use of this foot that it can move up 

 and down in its burrow, within certain 

 limits, or form a new one if necessary. 

 If a Clam be placed upright in some sand at the bottom of a glass 

 vessel of salt water it will need only careful watching, with perhaps a 

 little experimenting, to show that there is a current flowing into one of 

 the tubes— that away from the hinge side and the larger— and a current 

 out of the other, or the smaller one towards the hinge side. The 

 dissection of another specimen will show the internal organs in position,. 



Wantte 



Toot 



Shell 



Fig. 



18. — J/ya arcnaria. 

 One-half natural Size. 



