INLAND FISHERIES. 89 



The utility of tliis luibit is well illustrated in a circumstance 

 wliicli recently came under my observation at tlie liouse-boat 

 laboratory, in the Kickemuit Narrows, belong-ing to the Rhode 

 Island Fish Commission. I had suspended in the water a box 

 filled with sand which I had taken from a neighboring- clam bed. 

 In the sand I had sunken some glass dishes, about three inches 

 in depth, and had filled these also with sand. Here I had allowed 

 a number of small clams to burrow. On the 5th of August, the 

 reg"ion was visited by a terrific wind storm, and everything con- 

 nected with the house-boat was pitched about furiously for more 

 than an hour. Upon examining the g"lass dishes afterward, I 

 found that all the finer- sand had been washed out of them, and 

 but a few small pebbles remained. On these, however, several 

 clams remained firmly attached, and this had prevented their 

 being washed away. AVhere the waves were breaking- on the 

 beach, the same thing was probably happening. Small clams 

 near the surface in their shall oav burrows were probably washed 

 out in great nundjers. Many of them were then thrown up per- 

 haps, and left to perish. I have been informed by clam diggers 

 that during- violent storms, when the tide is high, vast numbers of 

 small clams are sometimes thrown up on the beach, and left high 

 and dry to perish l)y the retreating tide. But while, under such 

 conditions, many meet destruction, the possession of a byssus 

 which is attached to pel:)bles and sand grains many times heavier 

 than the clam itself must be of immense advantage in tending to 

 keep the animal from floating ofi" from the bottom. 



THE BYSSUS THREAD. 



Reference has been made to the relatively large, plowshare 

 shaped foot which extends backward over the ventral side of the 

 visceral mass. The byssus organ, in which the secretion for the 

 thread is produced, is located in the usual position on the ventral 

 side of the foot, and far toward its posterior extremity. Its 

 position is indicated in Figures 2 and 3, in which, however, the 

 foot is represented as being projected forward to a considerable 



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