NATURAL HISTORY, TORONTO REGION 
deep water into shoal water near the shore; towards 
midsummer they retreat to the deep and cold parts 
of the lake, where they spend most of their time. In 
the autumn they again move in towards the shore, 
seeking their spawning grounds; these are chiefly. 
rocky reefs and shoals, composed of what is known 
as honeycomb rock. It is said that gravelly and 
sandy shoals are sometimes resorted to for spawning 
purposes, but this is doubtful. Spawning takes place 
in October and November, and may possibly be 
extended by some individuals, or under exceptional 
circumstances, into December; both the time of 
spawning and of incubation depend largely upon the 
temperature. The autumn movement commences in 
September, but does not become general until Octo- 
ber; the fish then continue to run in greater or less 
numbers until the spawning is ended, when they 
again retire to deep water for the winter. It is a 
curious fact that even during the spawning season 
a large number of Whitefish are always to be found 
in the deep water, but there is no evidence that they 
ever spawn there. 
26. Cisco. Lake Herring. Argyrosomus artedi 
(Lesueur).—The Cisco was formerly common in 
Lake Ontario. Of late years, however, it has not 
been taken there in any quantity. Its spawning sea- 
son is in November and early December. 
27. Long-jaw Herring. Lake Herring. Argyroso- 
mus prognathus (H. M. Smith).—This fish may read- 
ily be distinguished from any other Whitefish found 
260 
