134 FISHES OF PENNSYLVANIA. 

May and June. According to Professor John A. Ryder, of the Univer- 
sity of Pennsylvania, the egg of the white perch is very adhesive, and 
on this account is troublesome to hatch artificially. In the experiments 
made by him the eggs were taken upon cotton yarn, which was drawn 
up through a funnel into which the eggs and milt had been squeezed 
from the spawning fish. The cord, covered with the adhering eggs, was 
then wrapped upon a wooden reel and sent under cover of damp cloths 
to the central station, where they arrived in fine condition, almost every 
ege being impregnated. This system was devised and carried out 
under the superintendence of Col. M. McDonald. After reaching the 
central station the cotton cord with the adhering eggs was cut into 
lengths of ten or twelve inches and suspended in the glass hatching 
jars. The development was soon interfered with by the growth of 
fungus. When the wooden reel with the adhering eggs was introduced 
into a wide aquarium fungus also attacked the eggs as before but the 
results were somewhat more favorable. With the water at fifty-eight 
to sixty degrees Fahrenheit the eggs hatched out in six days. 
The white perch congregates in large schools and is one of the freest 
biters among fishes. The shrimp is one of the best baits, although 
worms, sturgeon eggs, minnows and strips of cut fish with silvery skin 
are equally effective. Dr. Abbott has known as many as twenty dozen 
to be taken with a line in a few hours, and Spangler mentions catches of 
six or seven hundred in a day by two rods, the fish ranging in weight 
from three-fourths to one and one-fourth pounds. He records good perch 
fishing from Fort Penn, at the head of Delaware bay, to considerably 
above Lambertville on the Delaware; also in all the tributaries of the 
Delaware river. One of the charges brought against the white perch 
is its destruction of the spawn of other fish, especially of the shad. 
152. Morone interrupta Git. 
The Yellow Bass. (Figure 72.) 
The yellow bass has an oblong body, its greatest depth equaling one-third of the 
total length without the caudal; the caudal peduncle is short and stout, its least 
depth three-eighths of the greatest depth of the body; the head is moderately large, 
nearly one-third of the total without thecaudal; the snout is as long as the eye, which 
is one-fourth as long as the head; the mouth is rather large, the maxilla reaching to 
below the middle of the eye, moderately expanded behind and bearing a few small 
scales; the preopercle is strongly serrate on its hind margin; scales on the cheeks 
below the eyein seven rows; the gill-rakers are moderately long and slender, twenty 
developed on the first arch, the longest about one-halfas long asthe orbit; the spines 
are longer and more slender than in the white perch; the spinous dorsal begins 
over the sixth scale of the lateral line; its base isas long as the head without the 
snout; the first spine is shortest, two-thirds as long as the eye; the fourth and longest 
is four-fifths as long as the base of the fin; the last is two-fifths as long as the fourth ; 
the spine in front of the second dorsal is one-half as long as the spinous dorsal base ; 
the first and longest soft ray is as long as the base of the fin and nearly three times as 
long as the last; the anal fin begins under the twenty-seventh scale of the lateral 
line; the base of the fin is one-half as long as the head; the first spine is one-third as 
long as the second and two-fifths as long as the third; the second is a little longer 
