80 NATURAL HISTORY OF AMIA CALVA LINNtEUS. 



eggs are seen on the bottom of the nest. The circling is then repeated, after which 

 the two fish again come together and eggs are laid. This alternate circling and 

 laying of eggs continues until four or five egg-laying periods have been passed 

 through." (Note-book.) In this case the spawning continued for one hour and 

 forty minutes and the nest then contained relatively few eggs. The next morning 

 the nest contained a much larger number of eggs. I have no doubt of the substantial 

 correctness of these details, which were twice clearly and once less clearly seen by 

 Peters. In no case was there seen any posing of the male with fins spread in front 

 of the female, such as occurs in some teleosts, nor was there any other evidence that 

 the male used his colors as a sexual excitant. Since spawning takes place chiefly 

 at night, such use of the colors of the male is not to be expected. He produces 

 sexual excitation of the female rather by biting, usually gently, and by stroking 

 her with his body and fins in passing. 



These observations show that the egg-laying is intermittent in character. In 

 addition to the direct observations given above, as to the length of time occupied 

 in spawning, we have that derived from the eggs in cleavage stages when taken 

 from the nest. My records show three cases in which the eggs were in two- to sixteen- 

 cell stages, one of four to eight, one of two to four, and one of eight to sixteen. In 

 the other cases of which I have notes the eggs are recorded merely as in early 

 cleavage. The table given by Whitman and Eycleshymer indicate^ that it takes 

 about three hours for the eggs to pass from the two- to the sixteen-cell stage, and 

 about one hour intervenes between the stages, so that from this evidence the time 

 occupied in spawning by a single pair of fish may be estimated to be between one 

 and three hours, which agrees very well with the actual observations. This con- 

 clusion is in harmony with that of Ayers, as quoted by Whitman and Eycleshymer, 

 though they themselves appear to consider the average period of egg deposition 

 as ten to fifteen minutes. Dean ('96) finds in one nest evidence of a period of 

 "about twelve hours, in another a period of about hah an hour." 



That two females may spawn in the same nest with an individual male is made 

 probable by the history of nest No. 35, as given above. Nests 4 and 41 have a 

 similar history, but in them it is less likely that the male parent was the same 

 throughout the history of the nests. Nest 4 was begun on April 19, and eggs 

 were laid in it at noon of April 25. On the morning of April 26 the nest had appar- 

 ently been abandoned and small sunfish (Eupomotis gibbosus) were found in it 

 presumably engaged in eating the spawn. At noon of the same day there remained 

 not more than half a dozen of the several thousand eggs originally laid in the nest, 

 and sunfish were still hovering about. At 2 p.m. it contained a male fish, absent 



