d2 Bulletin of Laboratories of Denison University [voi. xii 



If the cat fishes in the course of their aimless movements 

 along the floor of the aquarium touch a bit of meat with the 

 lips or barblets, it is instantly seized and swallowed. Food in 

 the immediate neighborhood of the fish is not discovered at 

 once, but after a time appears to affect the fish in some way, 

 probably through the sense of smell, as the maxillary barblets 

 begin to wave above more actively and finally the fish becomes 

 restless. He does not find the food, however, unless in the 

 course of his movements it actually touches some part of the 

 body. 



During the months of May and June, 1902, more system- 

 atic experiments were undertaken with these fish, and since 

 tliese experiments are typical for those subsequently performed 

 on other species of fishes I shall recount them in some detail. 

 At first a ievf specimens were taken out in a shallow tray and 

 the attempt made to feed them in various ways under close ob- 

 servation. They were, however, so much frightened by the 

 exposure to bright day light and by the proximity of the ob- 

 server, in spile of all precautions, that no reactions could be 

 obtained which were at all satisfactory. A bit of fresh meat 

 on a long handled needle could be thrust slowly toward the fish 

 as he lay quietly on the bottom, rubbed over his body, or on 

 tlie barblets, and even over the lips, without evoking a move- 

 ment of any kind in response. The same observations was 

 m:\de with the spotted suckers. The fishes in both cases had 

 been without food for several days and were very hungry, but 

 were obviously too much frightened to respond to the food 

 Stimulus. 



On another occasion the same conditions were prepared, 

 ex'jept that a few dead leaves were littered over the bottom of 

 tlie tray. The fish when placed in the tray immediately sought 

 the shelter of the leaves, and, after a suitable interval to enable 

 them to become accustomed to the place, the feeding experi- 

 ments were repeated Selecting a fish which was entirely con- 

 cealed under a large leaf save for a projecting barblet, a bit of 

 neat on a slender wire was gently passed down into the water 

 in such a way as to touch the projecting barblet. It was in- 



