The Relation of Mollusks to Fish in Oneida Lake 253 
Genus Anoponta Lamarck. 
3. Anodonta marginata Say. Fig. 41, No. 4. 
Found at four stations, but common only at one. It occurs 
both on exposed points and in sheltered bays. It is listed by 
Beauchamp under the names fragilis and lacustris, which are 
synonyms of marginata. Found in Tomahawk Lake, Traverse 
Bay, Isle Royale, and Saginaw Bay. In Tomahawk Lake it 
is found on an exposed sandy shore, in situations similar to 
those in Oneida Lake. In Saginaw Bay it lives in both a 
sandy and a mucky bottom in more or less protected situa- 
tions. It is eaten by the muskrat. 
4. Anodonta cataracta Say. Fig. 41, No. 1. 
Occurs at ten stations, almost always on an exposed shore 
or point, on a sandy bottom, or in sand between boulders 
on the points. It is the most abundant of the Anodontas. 
Listed as Anodonta fluviatilis and A. williamsti by Beau- 
champ. Cataracta is a fall breeder (long period), gravid 
females being observed in September and October, as 
recorded by Ortmann (1913, p. 293). This species is con- 
fined to the lower St. Lawrence drainage. It is eaten by 
the muskrat. 
5. Anodonta implicata Say. Fig. 41, No. 2. 
A common species, occurring at eight stations, always on 
an exposed point or shore, in a sandy bottom, usually between 
boulders. Recorded from Tomahawk Lake on an exposed 
shore. Not recorded by Beauchamp. Gravid females were 
observed in Oneida Lake in September and October, the soft 
parts not differing materially from those of cataracta. In 
Oneida Lake it is one of the most abundant of the paper- 
shell mussels. It is believed to be the shell figured by 
DeKay (1843, pl. 17, fig. 233) as Anodon exeurvata. Eaten 
by the muskrat. 
