70 NATURAL HISTORY OF AMIA CALVA LINNAEUS. 



The seventy-four males taken before April 27 were placed in the enclosure 

 back of the net as soon as caught, while the females were confined in crates. 

 Beginning with April 27 all fish were placed in the enclosure. 



The bottom on which the net was set was a soft ooze through which it was 

 possible to thrust the hand beneath the net, and therefore through which Amia 

 might force its way. It is of importance, then, to know whether the male fish placed 

 in the enclosure before April 27 were absolutely confined or whether they might 

 pass in and out of the enclosure through the ooze beneath the net. If they were 

 able to pass out, there may not at any time have been seventy-four males in the 

 enclosure, and some of the fish taken in the net may have been fish that had escaped 

 from the enclosure. This, however, would not affect the experiment, which depends 

 on having only males in the enclosure, not upon the number of such males. Those 

 familiar with the fyke net and with the behavior of fish toward nets will readily 

 agree that a fish attempting to enter the enclosure would first explore the net lead 

 and attempt to find an opening through it. In this attempt he would come upon 

 the mouth of the net funnel, enter it and be caught. The fish would not attempt 

 to pass beneath the net unless he had first explored the net lead and found no 

 opening. A fish which was attempting to escape from the bay and which had come 

 upon the net lead and explored it without finding an opening might attempt to pass 

 beneath the net through the bottom ooze. Yet this is extremely unlikely, since fish, 

 through long experience, have learned to pass around obstacles on the deep water- 

 side or over them, and are not wont to seek a passage by burrowing into the earth 

 beneath them. Before April 27 the enclosure then contained a large number of 

 male fish on their natural spawning grounds, and presumably no females. 



In this enclosure there were made from April 20 to April 26 twenty-four nests. 

 Previous to April 26 only five of these contained eggs. These five were in two 

 groups, one of two nests, and the other of three nests about five metres apart. There 

 were but few eggs in any one of these nests, and not more in all five than would 

 ordinarily be found in one well-filled nest. The eggs in all five nests were in as nearly 

 the same stage of development as the eggs in a single nest usually are. It is thus 

 probable that the eggs in these five nests were all laid by one or two females, and that 

 these females were in the bay before the fyke net was set. These experiments seem 

 to me to show two things. 



First, the experiment of 1900 shows that the whole number of males seeking 

 the spawning ground during the breeding season is about four times the number of 

 females. This is true if no fish escaped from the enclosure, and indicates the ratio 

 of the sexes among sexually mature fish. In this connection it would be of interest 



