DISPERSION OF FRESH-WATER FISHES. 129 
faunze of Lake Tahoe and Utah Lake must be 
chiefly due to influences which have acted since 
the glacial epoch, when the whole Utah Basin was 
part of the drainage of the Columbia. 
Connected perhaps with changes due to glacial 
influences is the presence in the deep waters of the 
Great Lakes of certain marine types! as shown 
by the explorations of Professor Sidney I. Smith 
and others. One of these is a genus of fishes,” of 
which the nearest allies now inhabit the Arctic 
Seas. In his review of the fish-fauna of Finland,? 
Professor A. J. Malmgren finds a number of Arctic 
species in the waters of Finland which are not 
found either in the North Sea or in the southern 
portions of the Baltic. These fishes are said to 
“agree with their ‘forefathers’ in the Glacial 
Ocean in every point, but remain comparatively 
smaller, leaner, almost starved.” Professor Lovén # 
also has shown that numerous small animals of ma- 
rine origin are found in the deep lakes of Sweden 
and Finland as well as in the Gulf of Bothnia. 
These anomalies of distribution are explained by 
Lovén and Malmgren on the supposition of the 
former continuity of the Baltic through the Gulf 
of Bothnia with the Glacial Ocean. During the 
second half of the glacial period, according to 
Lovén, “the greater part of Finland and of the 
1 Species of JZysis and other genera of Crustaceans, similar 
to species described by Sars and others, in lakes of Sweden and 
Finland. 
2 Triglopsis thompsoni Girard, a near ally of the marine species 
Acanthocottus quadricornis L. 
8 Kritisk Ofversigt af Finlands Fisk-Fauna: Helsingfors, 1863. 
4 See Giinther, Zoological Record for 1864, p. 137- 
9 
