FISHES OF PENNSYLVANIA. 81 

head. The least depth of the caudal peduncle is a little more than one-third greatest 
depth of body. The head is large and the snout somewhat obtuse. The eye is in 
front of the middle of its length, a little more than one-half as long as the snout, and 
about one-sixth length of head. The dorsal fin is about midway between tip of snout 
and root of tail. The length of its base equals about half greatest depth of body. 
The longest ray equals equals length of ventral. The ventral origin is a little 
behind the middle of the dorsal. In the male when laid backward it reaches nearly 
to the vent. The length of the appendage equals that of the eye. The anal base 
is two-thirds as long as the ventral; its longest ray equal to ventral. The adipose 
fin is short and stout. Its width two-thirds of its length and about two-thirds length 
ofeye. D. 10; A. 9. Scales in lateral line 225 to 235; 6 gill rakers above the angle 
of the first arch ; 11 below. 
The coloration is very variable with age and locality. The upper parts are usually 
grayish much mottled with dark olive or black. The dorsal fin and anterior portion 
of caudal base and top of head are also mottled. The caudal has narrow dark bars. 
The lower fins dusky with a creamy white anterior edge bounded behind by anarrow 
black streak. On the sides numerous pale brownish blotches encircling small ver- 
milion spots. 
Distribution.—The brook or speckled trout of the east is indigenous to 
the region east of the Allegheny mountains and the Great Lake region, 
extending from Georgia on the south to Labrador on the north. In 
Pennsylvania it is most abundant in the southeastern portion of the 
state and particularly in Pike and Monroe counties. The distribution 
of this trout has been wonderfully extended by artificial introduction, 
as it has always been a favorite with fish culturists. It is now to be 
found thriving in many of the western states and territories, and is par- 
ticularly thrifty in Nebraska, Colorado, Nevada and California. It has 
also been sent to Mexico and to European countries. In Pennsylvania 
the Fish Commission distributes millions of this species annually. 
Size.—The average brook trout seldom exceed seven or eight inches 
in length, and smaller individuals are much more abundant and require 
legal protection. In the northeastern part of its habitat the brook trout 
grows much larger, specimens weighing from three to six pounds being 
not uncommon, and in one of the Rangeley lakes an individual weigh- 
ing eleven pounds is recorded; while Seth Green took a twelve-pound 
specimen in the Sault St. Marie, and Hallock mentions one which was said 
to weigh seventeen pounds. 
Habits.—The book trout does not flourish in water warmer than 68°, 
and prefers a temperature of about 50°. It is an inhabitant of the cold 
clear mountain streams, and will leave a region which becomes polluted 
by mill refuse and other hurtful substances. In the Long Island region 
and around Cape Cod where the brook trout has free access to salt 
water, it has the habit of going to sea in the fall and remaining during 
the winter. It then grows rapidly and becomes a much more beautiful 
fish than many which live exclusively in fresh water. In hot weather 
when the temperature of the streams becomes too high and lakes are 
accessible, trout seek the deep parts of the lakes and the vicinity of 
cold springs. In streams they are to be found in deep pools or in chan- 
6 FIsHEs. 
