256 



in shallow water, and occur scattered along the east side of the lake 

 a little way out from the shore. A good mussel bed is found in Lost 

 Lake along the east shore, extending from a little south of the Bardsley 

 cottage to where the bullrushes and water lilies grow thickly in the 

 soft black muck near the shore. 



Movements. — Closely connected with the question of distribution is 

 that of movement. The greater number of mussels of the lake, espe- 

 cially in the deeper water, spend their lives in a state of quiescence. 

 Young mussels appear to be more active than older ones. The mussels 

 retain the power o^ locomotion during all their lives, but after they 

 have got well settled down, they only occasionally use this power. The 

 mussels in shallow water near the shore move into greater depths at 

 the approach of cold weather in late autumn or early winter and bury 

 themselves more deeply in the sand. This movement is rather irregular 

 and was not observed every year. It was strikingly manifest in the 

 late autumn of 1913, when at one of the piers off Long Point a large 

 number of furrows was observed heading straight into deep water, 

 with a mussel at the outer end of each. The return of the mussels to 

 shore during the spring and summer was not observed. Many of them 

 are probably washed shoreward by the strong waves of the spring and 

 summer storms, and some are carried shoreward by muskrats and 

 dropped there. Occasional mussels were observed moving about in 

 midwinter, even in rather deep water. During the winter of 1900-1901, 

 an example of Lampsilis luteola, in rather deep water in the vicinity of 

 Winfield's, was observed to have moved about 18 inches in a few days. 

 Its track could distinctly be seen through the clear ice. 



As a result of the quiescence of the lake mussels, the posterior half 

 or third of the .shells, which projects up from the lake bottom, is usually 

 covered by a thick marly concretion which appears to be a mixture of 

 minute algae and lime. This marly concretion grows concentrically, 

 forming rounded nodules, its development increasing with the age and 

 size of the shell. This concretion, though most abundant on shells, is 

 not confined entirely to them, but grows also on rocks that have lain 

 undisturbed on the bottom. When growing on shells, it adheres to them 

 very closely; and upon being pried loose sometimes separates from them 

 ,nuch as the matrix separates from a fossil, and leaves the epi- 



