352 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
panels they were taken up with a hand net and transferred to universal jars for 
development. Fertilization was in every case accomplished by the fish themselves j 
and to a degree of perfection that was quite surprising. It was very rare that im- 
pregnation failed. 
The spawn from a fish consisted of a single free mass, light gray in color, tough 
and gelatinous. Figs. 1 and 2 accompanying represent the eggs before and after they 
were spawned. The forked extremity (Fig. 1) represents the anterior or forward end 
of the roe. After the roe had been spawned and fertilization and water hardness were 
accomplished its appearance was greatly changed (Fig. 2). On March 19 one of the 
fertilized and distended lobes of eggs was found to measure 26 inches. On the 20th 
William Maynard, night watchman, entered on his report: “ Found string of eggs 
from a large perch, measuring 47 inches long by If inches wide.” And again, on the 
30th: “ Found spawn from a large perch, measuring 7 feet 4 inches long by 4 inches 
wide at one end and 2 at the other, and weighing 2J pounds.” Continuing, he says : 
“After the act of spawning the old fish lay on her side for some time as if she would 
die.” “Also found,” he says, “that the strings of eggs are like an old-fashioned 
knitted coin purse, that is, a pocket closed at the ends.” 
When one of these lobes of eggs was found directly after being spawned the exist- 
ence of numerous transverse folds allowed the drawing or stretching-out of The mass 
to many times its original length. After being drawn out and again released it would 
partially contract and with the hands could be shoved back so nearly into the original 
compass that it approximately resumed the shape it had previously inside the parent 
fish (Fig. 1). The arrangement of the transverse folds corresponds in structure to 
the leather sides of the bellows or accordion. As soon as plumped up by water absorp- 
tion these numerous folds became so greatly distended as to stand prominently out 
in rounded curves to meet the surrounding element at every portion of the surface. 
Close examination of the egg-lobe revealed the existence of an interior passage 
throughout its length. The inner cavity was almost entirely closed, being, however, 
slightly open to outside communication by means of occasional small apertures in the 
walls. These openings were so unimportant in size and number and of such irregular 
shape and occurrence that they were at first regarded as accidental. Commissioner 
McDonald, however, suggested that they formed a part of the system of natural cir- 
culation and therefore were probably essential to aeration, and further examination 
tended to support this view. The egg-lobe was characterized by great springiuess, 
being in fact so highly vibratory that the least agitation of the surrounding water 
put the whole in motion. This movement evidently forces the water out and in, and 
hence the apertures seem to be a part of the design, which is a variety of pumping 
apparatus, for throwing out the stale water and taking in fresh supplies. Whether, 
in nature, the aerating vibrations are. dependent upon the fin-motion of the parents 
standing sentinel or on external agitation, as the motion from waves or currents, 
was not determined. 
The eggs of the yellow perch are slightly smaller than those of shad, but to make 
allowance for tissue those under immediate consideration were measured on the shad- 
egg basis, viz : 28,000 to the liquid quart. The measuring was done the first week in 
April, some days after the spawning was completed. Practically there was no loss 
during development and hatching except that brought about voluntarily in exami- 
nations. Of the eggs, 91,000, of March 23, were destroyed in making drawings and in 
