72 Bulletin of Laboratories of Denison University. [Voi. xii 



fins are far forward under the throat. In the pollock they are 

 but little modified, in the torn cod two rays are about twice as 

 long as the others and for about half their length they project 

 freely below the rest of the fin. In the hake all of the rays 

 of this fin are suppressed save these modified free rays, so that 

 the fin is filiform, branched at the end. Microscopic examina- 

 tion shows that the terminal buds are more abundant on the 

 more highly modified fins. The hake also has a free filament 

 on the dorsal fin produced by the extension of the third and 

 fourth rays beyond the others. I have not examined this free 

 filament microscopically, but know that it receives communis 

 fibers from the r. lateralis accessorius and have no doubt that 

 it also has numerous terminal buds, as the experiments show it 

 to be very sensitive to gustatory stimuli. The pollock have very 

 large eyes and are excellent visualizers. When food is thrown 

 into the water they dart for it and in general they take their 

 food by the visual reflex. So keen is the vision that it would 

 be difficult to carry on any experiments such as I have done 

 with the other two species without first blinding the fish. Nor 

 do they habitually drag the bottom with the free ventral fin 

 rays as the others do. I have therefore not devoted much at- 

 tention to this species, preferring to study more carefully those 

 species in which the gustatory reflex plays the greater part in 

 the life of the fish. 



Ihe hake [Urophycis iemds). These fishes, like the torn 

 cods, readily adapt themselves to life in captivity and are easily 

 experimented upon in small tanks. They are excellent visual- 

 izers, though not so much so as the pollock. When bits of 

 meat are thrown into the water they usually catch them 

 before they fall to the bottom and their keen vision makes 

 difficult such experiments as I carried on with the cat fishes. 

 They do not seem to recognize by sight food lying on the bot- 

 tom, but only when it is in motion. But bits of meat, fish or 

 clam lying on the bottom are usually found by the aid of the 

 free ventral fins. These fishes spend much of their time in 

 slowly swimming in an apparently aimless manner close to the 

 bottom of their tank. During these movements the filamen- 



