290 Salmonide 
this species is fair, but much inferior to the whitefish. Its 
geographical distribution is essentially the same, but to a greater 
degree it frequents shoal waters. In the small lakes around 
Lake Michigan, in Indiana and Wisconsin (Tippecanoe, Geneva, 
Oconomowoc, etc.), the cisco has long been established; and 
in these waters its habits have undergone some change, as has 
also its external appearance. It has been recorded as a distinct 
species, Argyrosomus sisco, and its excellence as a game-fish has 
been long appreciated by the angler. These lake ciscoes remain 
for most of the year in the depths of the lake, coming to the 
surface only in search of certain insects, and to shallow water 
only in the spawning season. This periodical disappearance 
of the cisco has led to much foolish discussion as to the proba- 
bility of their returning by an underground passage to Lake 
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SSIS 
sos: 
<a 
Fie. 220 —Bluefin Cisco, Argyrosomus nigripinnis Gill. Sheboygan. 
Michigan during the periods of their absence. One author, con- 
founding “‘cisco’’ with “siscowet,’’ has assumed that this under- 
ground passage leads to Lake Superior, and that the cisco is 
identical with the fat lake trout which bears the latter name. 
The name “lake herring’’ alludes to the superficial resemblance 
which this species possesses to the marine herring, a fish of quite 
a different family. 
Closely allied to the lake herring is the bluefin of Lake Michi- 
gan and of certain lakes in New York (Argyrosomus nigripinnis), 
a fine large species inhabiting deep waters, and recognizable 
by the blue-black color of its lower fins. In the lakes of central 
New York are found two other species, the so-called lake smelt 
(Argyrosomus osmeriformis) and the long-jaw (Argyrosomus 
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