444 PAKENTAL CARE AMONG FRESH-WATER FISHES. 



On July 5, between 10 and 11 a. ui., the eggs were deposited in four separate 

 agglutinated masses on the clean slate bottom. Unfortunately the fish were 

 not under observation at this time, although they were watched for about 

 fifteen minutes after the extrusion of the first two lots of eggs, when it was 

 supposed the spawning had been completed. The masses of eggs were of 

 nearly uniform size, about 4 inches long, 2i inches wide, and half an inch thick. 

 The newly laid eggs are one-eighth of an inch in diameter, nearly transparent, 

 and of a pale yellow color. 'J'he number of eggs deposited was estimated 

 at 2,000. The incubatory period was five days in a mean water temperature 

 of 77° F., the lowest temperature being 75° and the highest 80°. About twelve- 

 hours inteivened l»etween the hatching of the first and last eggs. Active move- 

 ment was observed in the embryos forty hours after the eggs were laid. Fully 

 90 per cent of the eggs hatched into normal fry, a few weak and deformed 

 fry and a few unfertilized or dead eggs being noticed. 



Smith and Harron entered into detailed observations respecting 

 the behavior of the- male and female catfishes tow'ard each other and 

 their nest making. 



The nest-making, as modified by the artificial conditions of the aquarium, 

 consisted in removing all the stones and sand from one end and keeping the 

 slate bottom scrupulously clean from all foreign objects, even the smallest 

 particles of food, sediment, etc. In moving the pebbles, which were mostly 

 from one-half to three-fourths of an inch in diameter, the fish took a vertical 

 or slightly oblique position and sucked a pebble into the mouth, usually beyond 

 the lips and out of sight, then swam toward the other end of the tank and 

 dropped it by an exj^losive or blowing effort. Sometimes the gravels were 

 carried only a few inches and sometimes the entire length of the aquarium. 

 Usually the fish swam horizontally near the bottom when carrying a stone, 

 but sometimes turned obliquel.v upward and dropped it from near the surface. 

 Both fish participated in this operation. The removal of finer sediment was 

 effected by a quick lateral movement of the body which caused a whirl that 

 lifted and floated the particles bejond the limits of the nest. 



The pair of fish more i)articularly under consideration, during the first night 

 the.v were in the aquarium, removed all the gravel from over a space nearly 

 2 feet long and IJ feet wide, upward of a gallon of stone being transferred as 

 described. After the second pair of fish had cleared a similar space, a pint or 

 more of gravel was' scattered on the nest ; the fish immediately began to re- 

 move the stones, and in a few minutes had completely freed the nest from 

 gravel. The gravel — regarded by bass and other fishes as desirable material 

 for the bottom of nests — may be i-emoved by the catfish for two reasons: (1) 

 To have a clean place for the eggs and young, so that they may be better 

 guarded, as hereafter described; (2) to provide a smooth place on which to 

 rest and against which to ml) the abdomen. , 



All the observations thus far noticed were made on individuals 

 confined in aquaria and of the species Amciurns catus or A. nebulosvs. 



The best account of the manner and location of nesting under 

 natural, or sometimes rather unnatural, conditions, has been given 

 by Albert C. Eyclesheimer, who had good opportunities to see the 

 common bullhead of the north (Atneii/rus nelndosiis). The observa- 

 tions were made in June, LSOO and 1898, in Wisconsin and Michigan. 

 June 8, 189G, three nests were found in Fowler Lake, Wisconsin. 



