992 FISHES—COTTIDA. 
black as when first seen, but of a light gray colur. This change of color from black to 
gray takes place in five minutes, and sometimes even less, aud changes completely the 
appearance of the fish. This rapid change of color was so new to me that it was demon- 
strated over and over again to make sure there was no mistake. The cause seemed 
to be the great fright and the light. Upon studying them more carefully in an aquarium, 
it was found that when the water became deprived of its oxygen they would pant like 
a suffocating animal, and become very pale just as they did when frightened. If the 
water is changed, these pale fish soon regain their natural color and respire slowly and 
regularly. | 
‘‘Té has been known to fishermen from time immemorial that many fishes imitate the 
bottom on which they live, changing their color whenever put upon a differently colored 
bottom. This fact has been recently studied with great care, and has been very satis- 
factorily explained. It was found that the skia contained very many pigment cells, 
which may be expanded into thin sheets or contracted into almost invisible dots. These 
cells are of three colors, black, red, and yellow, the black being most abundant. As 
they are intimately mingled together, it is evident that a great variety of shades may 
be produced by a suitable combination of the colors. If the black cells were contracted, 
and the red or yellow cells expanded, the fish would be red or yellow, or if the red cells 
were expanded in certain regions, the yellow in others, and the black in others, a spotted 
or striped appearance would be given. It was also found that if a fish were put upon 
differently colored bottoms frequently, it soon became able to change its color very much 
more quickly than at first. 
‘Tf the eyes be blinded no change in color takes place, but if the eyes are left perfect, 
and a spinal nerve be cut, then the skin supplied by that nerve remains of a natural 
tint, although the surrounding skin whose nervous supply has been unaffected, will 
change through its whole range of colors. : 
‘‘There is one point in the character of the Star Gazer, which is, so far as I know, 
unique with fishes. If one be carefully watched at a considerable distance, the respira- 
tions, indicated by the alternate opening and closing of the mouth and gill fissures, will 
be seen to take plase about forty times per minute. Now, if one suddenly moves up very 
near the fish, not the slightest motion of the body or of the respiratory apparatus can 
be detected. If, however, one remains periectly still for about half a minute, and 
watches the gill covers, he will see them commence to rise and fall very gently, and in 
two or three minutes the respirations will be as vigorous as ever. This experiment may 
be tried over any number of times and always with the same result. This is equiva- 
lent to holding the breath with the higher animals, and is apparently for the same pur- 
pose; viz, to escape detection. This supposition is verified by the following observa- 
tion. As was stated above, a fish in impure water respires very rapidly and with des- 
perate effort. No matter how suddenly one moves near a fish in this condition, not the 
slightest notice is taken of it; that is, the distress of sufiocation has rendered the fish 
indifferent to its surroundings. 
‘The parental instincts of the Star Gazer are no less interesting than its purely selfish 
ones. If une goes to the west shore of the lake from April to July, and lifts up flat 
stones in water twelve to fifty centimetres deep, there will be found clinging to the 
under side of many of them an irregular, conical mass of beautiful salmon colored eggs, 
and under the same stone a Star Gazer. If the fish be frightened away, but nothing 
else disturbed, it will return in a short time as if to take charge of the eggs. The eggs 
are those of the Star Gazer, as is proved by hatching them ; and the belief that the fish 
