84 



NATURAL HISTORY OF AMIA CALVA LINNMJS. 



In order to see whether the male is on the empty nest more often than on that 

 containing eggs or is on the nest in the morning more often than in the afternoon, 

 the following table was made. It shows the total number of visits made to the 

 sixty-seven nests of the years 1898 and 1899, omitting those visits made after the 

 nests showed signs of deterioration, as though abandoned. It shows also the num- 

 ber of times when both the empty nests and the nests containing eggs were guarded 

 in both morning and afternoon. 



Table V. 



From this it appears that the empty nests were found guarded quite as frequently 

 as those containing eggs, and that the fish were found on 63% of all nests visited in the 

 afternoon and on only 28% of nests visited in the morning; that is, they were absent 

 from the nests about twice as often in the morning as in the afternoon. I have 

 visited nests at night only for the purpose of securing precleavage stages, and have 

 therefore visited chiefly empty nests, and these during only a part of one season, in 

 which, as it proved, a large number of the empty nests were abandoned. In one 

 hundred and sixteen such visits at night the fish was found in twelve cases or in 

 about 10%. These visits were made to twenty-four nests, of which but three were 

 subsequently spawned in, so that it is likely that many of the visits were made after 

 the nests had been deserted. It is possible that the males are often absent from 

 empty nests at night and in search of the females, but this point could be best deter- 

 mined by records of night visits to empty nests which were subsequently spawned 

 in, as well as to nests containing eggs. 



While the male guards the nest he lies for the most part motionless or with 

 only slight movements of his fins, but at intervals he moves over the nest and thus 

 by the movement of his fins keeps the eggs free from sediment, which would other- 

 wise soon smother them. With the sediment the fungus spores are doubtless also 

 removed. At the same time the male keeps away other males which at times try 

 to occupy his nest. This I have seen twice. In one instance the two males were 

 seen in the same nest, which was at the time empty. One of them turned suddenly, 

 and rushing at the other struck him with his head in the middle of the side and 

 hurled him two feet from the nest. In the second case a nest containing eggs and 

 guarded by a male fish was approached by a second male, which came to within 30 



