NO. 1861 the; arche;r-fish and its fe;ats — gill 281 



downward head foremost ; it rarely, indeed, sees what is at the bot- 

 tom, and although worms may be there in abundance, it finds them 

 only when hunger impels it to search for them there. And it is not 

 alone the mobility of the eyes which engages attention; instead of 

 the expressionless stare which is characteristic of fishes generally, 

 the Archer's eyes sparkle with intelligence. Especially when the fish 

 becomes sick or is dying is expression manifested ; then it looks at 

 you as if it would implore your attention and would like to speak. 

 The gaze of one of Zolotnitsky's fishes, which was dying, produced 

 on him such a painful impression that he could never forget it! 

 Still another noteworthy feature exists. The eyes may be operated 

 jointly or severally; if the eye of one side is pushed outwards, the 

 opposite one may sink inwards. 



V 



Another characteristic feature is the susceptibility to external con- 

 ditions and its manifestation by change of color. The faculty of 

 changing the color of the body as well as the fins is, indeed, developed 

 to a high degree. Every change to which Zolotnitsky's fishes were 

 subjected was accompanied by a change in their colors. The want 

 of oxygen, the temperature of the water, clearness or cloudiness, 

 abundance or deficiency of food, good or bad health, fright, joy. 

 The color is in truth a barometer of their life. They avail them- 

 selves of this susceptibility or capability, too, in' assuming protective 

 and dissembling hues. When for example they had a nocturnal 

 feast, they discarded their bands and became greenish, accommodat- 

 ing themselves to the color of the water. Zolotnitsky, noticing this, 

 experimented. He covered the aquarium with a paper, — the fishes 

 soon settled to rest and assumed their normal banded condition ; 

 then the paper was removed and they immediately became greenish 

 again. He was with good reason astonished at the disappearance of 

 the bands and spots, and naturally puzzled to account for it. 



Not only is the coloration a barometer, it is also a thermometer ; 

 the fishes are very sensitive to the weather and show its graduations 

 by coloration of the body. At 70° Fahr. and upwards the colors 

 are clear and lively ; at 66° Fahr. they begin to fade, and at 60° Fahr. 

 or 61° Fahr., they are quite dull; a little further fall of temperature 

 entails loss of appetite and sluggishness. Zolotnitsky did not venture 

 to experiment with a temperature less than 55° Fahr. (10° R.), for 

 he was convinced that such would be fatal. (Zolotnitsky, 78, 80.)^ 



' The pages of the original are numbered in Roman figures. 



