OF NORTH AMERICA. 197 



BRITISH AMERICA. 



ONTARIO: Ottawa, Carleton Dist. (Heron); Hamilton, Wentworth Dist. 

 (Walton). 



GEOLOGICAL DISTRIBUTION : Unknown. 



ECOLOGY: But few collectors have studied the habitat relations 

 of this beautiful species and the writer takes great pleasure in quoting 

 the following account by Dr. Reynold J. Kirkland, of Grand Rapids, 

 Michigan : 



"On Thanksgiving Day, 1897, a collecting trip to Reed's Lake 

 was made. The day was bright, cold and windless ; the surface of the 

 water covered with a thin sheet of ice, not thick enough to greatly 

 interfere with wading. My quest was particularly for Pisidia. On 

 clearing my scoop, while standing in about two feet of water, I was 

 greatly surprised to find two examples of L. gracilis amongst the lit- 

 tle bivalves at the bottom. They had evidently been dislodged from 

 the rushes and had fallen into the scoop as it was being brought to 

 the surface. Further search for Pisidia was abandoned, and the fol- 

 lowing several hours were spent in sweeping the rushes with my scoop. 

 The result was over eighty specimens of this exquisite mollusk, a fine 

 sauce for the cold turkey that awaited my return home at dark. 



"Each fall save one since then, from one to a dozen trips have been 

 made to this spot, with varying success. One year four trips yielded 

 but five individuals ; while a single visit another year resulted in a bag 

 of nearly two hundred. 



''This is a deep water species, which migrates shoreward in the 

 fall, doubtless for spawning purposes, as adults only have been cap- 

 tured, but this should be verified by dissection. September 25th is the 

 earliest date they have been taken, and they remain until ice forms, 

 how much longer is not known. They are gregarious, or at least live 

 in colonies. This colony has occupied an area of not more than a 

 few square rods any one year; and the location of this area has not 

 varied a hundred feet in either direction during the ten years of its 

 observation. Rushes grow along about two miles of the shore line 

 of this lake. Systematic examination of perhaps a half mile of this 

 distance has failed to disclose another colony. The home of this mol- 

 lusk is on the rushes or reeds common to all our inland waters; in 

 water from one to three feet deep ; and invariably from six to eight 

 inches from the bottom, on the side of the reed facing deep water, the 

 apex of the shell pointing downwards, though in a few instances the 

 apex has been upwards, as if in the act of descending. Incidentally, 

 it may be remarked that Ancylus fuscus is abundant on these same 



