80 FISHES OF PENNSYLVANIA. 


ices between stones, under projecting roots of trees and sometimes in 
nests excavated by the spawning fishes. The parents cover the eggs to 
some extent with gravel. The hatching period varies according to tem- 
perature, from forty to seventy days. Females aged three years, fur- 
nish on the average about three hundred and fifty eggs each, but indi- 
viduals of this age have yielded as many as seven hundred, and even at 
the age of two years some females produce from four to five hundred. 
When four or five years old the number of eggs has reached fifteen hun- 
dred to two thousand. The young thrive in water with a temperature 
of about fifty degrees Fahrenheit. Sterility in the females is common 
and breeding females have been observed to cease reproduction when 
eight years old. 
(Jualities.—The brown trout is in its prime from May to the last of Sep- 
tember. Its flesh is very digestible and nutritious, and deeper red than 
that of the salmon when suitable food is furnished ; the flavor and color, 
however, vary with food and locality. Insect food produces the most 
rapid growth and best condition. This species has been so long known 
as one of the noblest of the game fishes and its adaptability for capture 
with artificial flies, because of its feeding habits, is so well understood 
that I need not dwell upon these familiar details. 
Genus SAL VELINUS (Nitsson) Ricsarpson. 
In Pennsylvania waters this genus of salmonide includes the well- 
known brook and lake trouts. They are distinguished from the salmon 
and river trouts most readily by the dentition of the vomer. The teeth 
are present only in a small rounded cluster on the head of that bone 
in the brook trout, and in the lake trout they are planted upon a raised 
crest or chevron which is not consolidated with the shaft of the vomer. 
The lake trout indeed is worthy of the separate designation—Cristivo- 
mer—assigned to it by Gill and Jordan in 1878. There is no difficulty 
in distinguishing the brook trout from the lake trout, the former having 
the typical teeth on the head of the vomer and a square tail, while the lake 
trout has a peculiar dentition and a deeply-forked tail. The coloration, 
also, would readily serve to distinguish the two at all ages. 
In the charrs the scales are very small; the sexes do not differ much 
in the prolongation of the jaws, although the male always has a much 
larger maxilla than the female. The typical sharrs :re usually small 
and the species are numerous, while the sub-genus Cristivomer is rep- 
resented by a single large and in many respects peculiar species. 
93. Salvelinus fontinalis (Mircs.) 
The Brook Trout. (Figure 7.) 
The brook trout varies greatly in the shape of the body, sometimes being short 
and deep and again elongate and moderately thin. The depth is usually about one- 
fourth or two-ninths total length without caudal, and is about equal to length of 
