252 College of Forestry 
PHYLUM MOLLUSCA. 
Crass PELECYPODA. 
ORDER PRIONODESMACEA, 
Famity MARrGARITANIDA. 
Genus Marcartrana Schumacher. 
1. Margaritana margaritifera (Linneus).* Fig. 40, No. 4. 
This widely distributed mussel is not common in Oneida 
Lake, being found only at five stations, always in an exposed 
habitat, usually at the end of a rocky point. The specimens 
collected are not large, none exceeding 65 mill. in length. 
The distribution of this mussel is the most extensive of any 
mollusk, including Europe, Northern Asia, Japan, Western 
America to below the 40th degree of latitude, East of the 
Rocky Mountains in the upper Missouri River, and in 
Saskatchewan, and in eastern North America, in Eastern 
Canada, New England, New York and Pennsylvania. Dr. 
Walker (1910) has recently described the unique distribu- 
tion in America of this almost cosmopolitan mollusk. 
Famity UNIoNIDs. 
Genus Exriprio Rafinesque. 
2. Hlliptio complanatus (‘ Solander,” Dillwyn). Fig. 40, 
No. 1. 
This is the most abundant mussel in the lake, being found 
at 32 out of 41 stations. It lives on a sandy bottom in both 
exposed and sheltered locations. It has not been found in 
bays where there is a thick mass of submerged vegetation. 
This species is found in Georgian Bay, but does not occur in 
the other localities mentioned in comparison. It is eaten 
by the muskrat. 
*The classification of the Naiadacea is that of Ortmann (1912) which 
is a modification of Simpson’s Synopsis (1900, 1914). 
