HABITS OF CHOLOGASTER. 85 



It was mentioned before that one fish, in the course of 4 hours, took n pieces of cotton from the 

 end of a thread and after that refused to take it again, although the fish was kept for several months. 

 In this case, then, it learned to discriminate within a very short time, and remembered the difference 

 between the cotton and the meat. It took the meat, if brought in contact with the lips, after it 

 refused the cotton. 



Another fish was tested by dropping water on the surface of the aquarium. The fish came to 

 the surface and grabbed at the drop. I tested the fish once everyday for 12 days, and on the twelfth 

 day it refused to grab, but came up near the surface, poised as if ready to grab, and then sank 

 slowly toward the bottom. The thirteenth day it responded, but not very readily. For the next 

 8 days I tested it every day and got no attempt at grabbing, although it came near the surface every 

 day. I did not test it again for 3 days, when it again snapped at the drop. It came up to the sur- 

 face at the first few drops, but sank gradually toward the bottom. Upon continuation of the drop- 

 ping, it came up again and grabbed. I then left it undisturbed for 5 days before testing and again 

 it grabbed. This was the twenty-ninth day of the experiment. I then started with an interval of 

 i day and increased it by i day each time, thus making the intervals i, 2, 3, 4, and 5 days. It 

 did not snap at the drop until after the interval of 5 days. This was the forty-fourth day of the 

 experiment. I again waited 5 days before testing the fish and got no response further than that 

 the fish came near the surface. On account of the lack of time the experiments were discontinued. 

 Whether the fish would eventually have learned not to snap at the drop, I can not say, but that 

 memory plays some part in its reactions is evident from my observations. 



The conclusions reached are as follows: 



(1) Sight is as a matter of course excluded from food seeking. 



(2) The olfactory sense, if any, plays a very minor part in detecting food. 



(3) The sense of taste enables them to discriminate between things in contact with the snout. 



(4) The tactile sense is the one by which they find and precisely locate their food. 



THE HABITS OF CHOLOGASTER. 



The following extract, from a letter from Mr. E. B. Forbes, is of interest: 



Doubtless you have received the little Chologaster which I sent you yesterday. The spring in 

 which they are found is in an almost inaccessible part of Jackson County and I drove 17 miles from 

 Cobden, Illinois, in a wagon to this place. The spring is a very large one, flowing from the bottom 

 of a 250-foot cliff of flint and limestone. The little fishes were found under stones at the edges of 

 the spring, very close to the bluffs, and when disturbed they swam back under the cliff. After the 

 rough drive home they were still alive and seemed vigorous when handed over to the expressman. 

 I found this species in other springs than the large one mentioned and have no doubt that it is rather 

 widely distributed. None were found at any considerable distance from the face of the cliff. 



I found that Chologaster agassizii acts similarly in the River Styx in Mammoth 

 Cave. As soon as my net touched the water they darted in under the ledge of 

 rock at the side of the little pool in which I found them. 



The Chologaster in general make-up is like Amblyopsis, but somewhat more 

 elongate. It sits with its pectorals extended. When it moves horizontally for some 

 distance the pectorals are usually pressed to the sides, the propelling being done 

 largely by the tail, very much after the manner of a salamander, which it resembles. 

 In swimming toward the surface it uses its pectoral fins chiefly, and the fish usually 

 sinks to the bottom as soon as its efforts to raise itself are stopped. 



Individuals kept in aquaria with one end darkened either collected in the dark- 

 ened area, floating about, or under leaves or sticks in any part of the aquarium. 

 They are frequently found under a floating board where they float with the tops 

 of their heads in contact with the board, their bodies slanting downward. 



Typhlichthys, living in total darkness, has retained the habit of staying under 

 floating boards and sticks and under stones. Miss Hoppin noticed that Trog- 

 Uchthys swims with its back to the aquarium, and I have repeatedly noted the 

 same in the young of Amblyopsis up to 50 mm., and the still younger Amblyopsis 

 frequently hides under rocks. 



