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The common Whitefish is the most important, abundant and widely distri- 
buted of these. It is distinguished by its compressed body, its elevated back— 
a peculiarity especially marked in the adult—and its small short head with 
obliquely truncated snout. 
C. quadrilateralis is rounder in body,(it is the Roundfish of Richardson) and 
further differs in having a larger head, stouter gill-rakers and a dark-blue colour 
of the back from the foregoing species, to the size of which it does not reach. It 
is commoner northward than in the Great Lakes. 
C. labradoricus is commoner towards the north-east, as its name suggests, 
but it is also found in Lake Superior and northward ; it has the compressed body 
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of the common whitefish, but the length of head of the Roundfish. It only 
attains a length of one foot, and has some teeth on the tongue which the white- 
fish lacks. A whitefish ofsimilar size occurring in the deeper waters of Lakes Michi- 
gan and Ontario is known as the Cisco in the former and as the “long-jaw” in 
the latter; it is distinguished by the bright silvery color of the under parts, but 
also by the smaller number of fin-rays (D 10, A 10.) and of the scales in a vertical 
row. In its larger mouth it approaches the Lake Herring (C. artedi), which 
occurs in immense shoals in the lakes and especially in Lakes Erie .and Ontario, 
and is, next to the Whitefish, the most important member of the group. The 
_ variety known in commerce as the Cisco of Lake Ontario, is a deep water 
form, much fatter than the ordinary Lake Herring, and bringing as much as one- 
third higher price on account of its making better kippers than the other. Lastly 
the Tullibee, which is commoner in Manitoba than in Ontario, is intermediate to a 
certain extent between the Lake Herring and Whitefish, but has the deep com- 
pressed body of the latter and scales which, being larger in front and peculiarly 
marked, are characteristic of this species alone. 
The Whitefish proper deserves special attention on account of its importance 
from the economical standpoint. As remarked above it exhibits considerable 
variation both in size and form. The largest fish are taken in Lake Superior, 
where they may weigh as much as 20 lb, whereas in Lake Erie they rarely attain 
to half that weight. The fish are mature when much smaller, the males being 
conspicuously smaller than the females. 
The observed variations in form are associated with a marked preference for 
adhering to some particular locality even in large bodies of water. This would 
seem to be incompatible with the migrations of the fish in the lakes, but it is 
probable that these movements are from deep into shallow water and vice versa. 
Fishermen at least are confident that Whitefish taken in different localities can be 
easily recognized, that those e.g. taken in the upper end of Lake Ontario are 
different from those in the lower end of Lake Erie; and that the fish e.g. taken in 
Batchewaung Bay, Lake Superior, are peculiar to that bay. Indians at the Sault 
say that the Whitefish of the lake above never descend the rapids, while those of 
the river never ascend to the lake. 
In Lake Ontario and also in the upper lakes, but not in Lake Erie, where 
the water is too warm, two shoreward movements are observed; the first occurs 
in June with the approach of warm weather and its object would appear to be 
the larve of the various aquatic insects which are then abundant. When the 
shallow water becomes too warm they retreat again into the deeper waters of the 
lake, where the shrimp-like erustaceaof these depths (Mysis relicta and Pontoporeia 
afinis) furnish them with abundant food. After a stay of two or three months, 
that is to say till about the middle of October, there begins the second shoreward 
movement, this time for the purpose of spawning, the spawning grounds being 
slowly reached towards the middle of November or the beginning of December. 
After this function has been successfully accomplished they retreat again into 
