The Relation of Mollusks lo Fish in Oneida Lake 257 
approaches /ufeola in size, shape, and markings so closely as 
to render absolute indentification almost impossible. 
Typically duteola has a smooth almost shining surface, with 
a few distinct, separated rays, while radiata has a rough, dull 
surface with many rays which are crowded together and 
more or less wavy. Gravid females of radiata were abund- 
ant in September. The soft parts did not differ from those 
of luteola. Specimens occur with a pink nacre, as in the 
variety rosaceus of Lampsilis luteola. The figures by Robert- 
son (1911, pl. XII, figs. 26, 80) resemble this species more 
than luteola. Iadiata is a favorite food of the muskrat. 
18. Lampsilis borealis (Gray). Fig. 44, Nos. 1-4. 
This mussel was collected at four stations, all similar to 
those of radiata. It is widely distributed, being reported 
from the Lake of the Woods east to the St. Lawrence drain- 
age. It was originally described from near Duck Island, 
Ottawa River, Ontario, Canada. It has not always been 
distinguished from radiata, which it most nearly resembles, 
and is not reported from any definite locality in New York 
(Letson, 1905, p. 82). It differs from radiata in being 
rounder and more inflated. As remarked by Simpson (1914, 
p- 64) it combines many of the characters of both luteola 
and radiata. ‘The figures on the plates bring out these differ- 
ences. Gravid females were observed in Oneida Lake in 
September. The soft parts do not differ from those of 
radiata or luteola. Waten by muskrats. 
14.. Lampsilis ris (Lea). Fig. 42, No. 2. 
This mussel occurred rarely at station XX, a bouldery, 
exposed point. None were gravid. It ranges from Illinois 
and Wisconsin east to New York. It is recorded from 
Saginaw Bay, as rare. Listed by Beauchamp under the 
names of iris and novi-eboract, the latter a synonym. 
