258 Canadian Record of Science. 



Quebec and Ontario. In the latter province unusually 

 large and thick specimens, measuring five inches and a 

 half in length by three inches in height, were collected by 

 Prof. Macoun, in 1894, in the east and west branches of 

 the Grand River, at Gait and Ayr. The species has been 

 recorded by Dr. G. M. Dawson as occurring, though 

 rarely, in the Roseau River, Manitoba. 



Margaritana undulata, Say. 



St. Lawrence River, at Montreal and Quebec, J. F. 

 Whiteaves, 1861. Near Ottawa City, G. C. Heron, 1879. 



UNIO, Philipsson, 1788. 



Unio alatus, Say. 



Widely distributed throughout Ontario. The most 

 easterly locality at which it has been collected is the 

 Ottawa River at L'Orignal, as recorded by Dr. R. Bell, in 

 the Canadian Naturalist and Geologist for June, 1859 

 (Vol. IV., p. 219). In Manitoba it has been collected in 

 the Red River by Dr. G. M. Dawson, in 1873, and by 

 T. C. Weston, in 1884. 



Unio borealis, A. F. Gray. 



A pair of specimens of this species, from the Ottawa 

 River, at Duck Island, the typical locality, was presented 

 to the museum of the Survey by Mr. F. R. Latchford, of 

 Ottawa, in 1886. 



Unio Canadensis, Lea. 



Two specimens, from the Ottawa River, near Ottawa, 

 which are believed by the donor to be referable to this 

 enigmatical species, were presented to the Museum of the 

 Survey by Mr. Latchford, in 1893. 



Unio circulus, Lea. (?= U. subrotundus, Rafinesque.) 

 Lake Erie, at Kingsville, Ontario, J, McQueen, 1880, 



