104 
FIFTEENTH REPORT. 
THE BREEDING HABITS OF THE LOG-PERCH 
CAPRODES). 
PERCINA 
BY JACOB RE IG HARD, PRELIMINARY ACCOUNT. 
Hitherto the breeding habits of the darters have remained practically 
unknown except in the case of the rainbow darter, Etheostoma coer- 
ulcum, which was studied at Ann Arbor by Miss Reeves. 
The log-perch is rarely seen in Douglas Lake and seems to be an inhab- 
itant of the deeper waters, though a few individuals have been seen by 
Mr. Heimburger on the bottom in three or four feet of water. During 
the eleven days beginning June 29. the fish were breeding on the pure 
sand bottom near the camp in water from four to twelve inches deep. 
About 150 fish were under observation. Sexes are distinguishable when 
Hie fish are at liberty bv the darker coloration and bv the behavior of 
«. tv 
the male, and in captivity by the larger anal tin of the male. 
The breeding males are found in groups of 15 or less. Among these 
are a few females, but most of the females are seen waiting in deeper 
water or about the borders of the group. When a female enters the 
group she is at once pursued by one or more males, usually by many. 
She continues for some time to flee in a tortuous course back and forth 
through the group in its neighborhood. The female finally settles to 
the bottom and a male takes position over her with his pelvic fins clasp- 
ing her head and his tail at the side of hers. A rapid vibration of the 
fail, pectoral and pelvic fins of both fish then follows and lasts about 
four seconds. This sends backward a whirl of sand and excavates a 
little pit in the sand beneath the fish. During this time, the eggs are 
emitted and fertilized and are usually buried in the sand, some in the 
pit, others behind it. Each egg is weighted by a coating of adhering- 
sand grains. The spawning pair is usually enveloped by a group of 
supernumerary males, which are attempting to supplant the pairing 
male. When the spawning is completed, the spawning fish leave the pit 
or at least the female does so. She repeats the spawning in many 
other pits. When the spawning is finished at a pit the supernumerary 
males (and perhaps the pairing male) at once surround the pit and 
devour such eggs as they can get. The eggs were found in their stomachs. 
The eggs and young receive no care from their parents, but these, when 
the spawning period is ended, go into deeper water and are not again 
seen. The spawning behavior of this darter is more generalized than 
that of Etheostoma coeruleum, since each male ranges over the whole 
spawning ground, while in E. coeruleum, each restricts his activities to 
a small part of the ground, from -which he excludes the others. 
The spawning behavior is further of interest because it furnishes an 
instance in which sexual dimorphism in color occurs, and yet this differ- 
ence is not the basis on which the fish themselves discriminate between 
the sexes. Young males in full color were often pursued by other males, 
and were apparently distinguished from them only by their failure 
to stop and behave like females. By the experimental substitution of 
