EGGS AND LARVM OF A SEA-BULLHEAD. 295 



the larva must have travelled at the rate of about one inch in 

 four seconds. 



At the end of the fifth day after hatching the average length 

 of the larvae was 5*5 mm., and their ability to keep a straight 

 course through the water was still more marked. There seemed 

 also to be a decided tendency towards swimming in a horizontal 

 position. The larvae appeared, however, to be almost helpless, 

 and when touched with the point of a pencil made at most a 

 little jerk away from it. Eepeated touches with the point of a 

 pencil merely resulted in repeated horizontal jerks, and did not 

 cause the larvae to seek safety by diving deeper into the water ; 

 nor did agitation of the water by a pencil held close to any larva 

 seem to alarm it. 



On the sixth and seventh days the larvae began to give 

 indications of inability to swim vigorously, and to lie for longer 

 and longer periods on the bottom. They now began to die off 

 rapidly, the last one dying on February 26th, that is, on the 

 ninth day after hatching began. Those placed in the bowl of 

 still water did not live beyond the end of the second day. 



During the night of February 20th-21st (i. e. on the twenty- 

 fourth day after laying, and on the fourth day after hatching 

 began) the Bullhead laid another, and smaller, mass of eggs. 

 The number of eggs in this mass was not more than eight 

 hundred, the great majority of which developed so far as to be 

 ready for hatching, although only about thirty actually hatched 

 out, the remainder dying at this stage. The egg-mass was 

 transferred to a fresh tank on the morning of March 15th (on 

 the twenty-third day after laying), and on that day and the next 

 hatching went on, as it had done when the first mass was 

 removed. None of the larvae from this second mass lived beyond 

 the end of the fourth day. It may again be pointed out that 

 there seemed to be no possibility of the eggs being fertilized in 

 the aquarium. 



Would the Bullhead have laid the second mass upon the first 

 if the latter had not been removed ? It seems probable that it 

 would, because, as already mentioned, the fish had returned to 

 the first egg-mass on the second day and remained on it for 

 about two hours. The water in the tank was fourteen inches 

 deep, and the first mass of eggs was laid in a situation in which 



