PISCES, TRUE FISH 471 



A. nehulosus, the brown bullhead. This being the case and since the 

 two are very similar, a brief description will be given for the latter. 

 The observations were made on a pair in an aquarium in AVashing- 

 ton, D. C. They made a nest on July 3 by removing with their 

 mouths more than a gallon of gravel from one end of the tank, 

 leaving the slate bottom bare. On July 5 about two thousand eggs 

 were deposited in four masses. Ninety-five per cent of them hatched 

 in five days with the water at 77° F. The young remained in masses 

 until six days old; then they began to swim. By the end of the 

 seventh day they were swimming actively and most of them collected 

 in a school just beneath the surface, where they remained for two 

 days, afterwards scattering. It is also reported that they ate finely 

 ground liver on the sixth day and had enormous appetites after the 

 eighth day. They were 4 mm. long when hatched and had attained 

 a length of 18 mm. by the fourteenth day. At the age of two months 

 their average length was 50 mm. Both parents assume responsibility 

 in caring for the eggs, keeping them agitated constantly by a gentle 

 fanning motion of the ventral fins. The egg masses are also sucked 

 into the mouth and then blown out with some force. These opera- 

 tions were continued until the fry (newly hatched fish) swam freely. 



