PAREiS'TAL CARE AMONG FRESH-WATER FISHES. 443 



further interest in them, the whole duty of renewing and forcing the 

 Avater through the mass of adherent ova devolving upon the " other, 

 " who was most assiduous in this duty until the young had escaped 

 from the egg membranes." During the week this incubation lasted 

 the writer daily visited the aquarium, but did not remain long. By 

 Ivvder and the immediate attendant it "• was at first supposed '" that 

 the Avatcher was '' the female," but the writer contended that it was 

 rather the male. Ryder explained that " on the 30th of June, or when 

 the young were seventeen days old, it was determined to make an ex- 

 {?mination of the internal organs of both parents, which was done in 

 the presence of Professor (lill, to learn Avhich one of parent fishes it 

 was that had acted as nurse; " it was found that it was the male. 



Not only did the male alone act as guardian of the eggs, but on one 

 occasion during the w riter's observation, when the female approached 

 nearer than she Avas wont to do, the male advanced toward her and 

 butted at her Avith partly open mouth. Occasionally, hoAvever, the 

 female may cooperate Avitli her mate, if Ave may trust to the observa- 

 tion of Hugh. M. Smith and L. G. Harron (1908) Avhich were more 

 extended than Ryder's or mine, and are Avorthy of reproduction. 



During the entire liatehing period l)oth parents were incessant in tlieir effoi'ts 

 to prevent tlie sniotliering of tlie eggs, to Iceep them clean, and to guard against 

 intruders. The eggs were Icept constantly agitated and aerated by a gentle 

 fanning motion of the lower fins, and foreign particles, either on the bottom 

 of the nest or floating near the eggs, Avere remo\-ed in the mouth or by tlie 

 fins. The most striking act in the care of the eggs was the sucking of tlie egg 

 masses into the mouth and the blowing of them out, this being repeated sev- 

 eral times with each cluster before another lot was treated. 



The male was particularly active in watching for intruders, and savagely 

 attacked the hands of the attendant who brought food, and also rushed at 

 sticks or other objects introduced into the aquarium. Practically the entire 

 work of defense was assumed by the male, although the female occasionally 

 participated. 



During the time the fry was on the bottom the attentions of the parents 

 were uurelaxed and, in fact, were increased, for the tendency of the different 

 lots to become scattered had to be corrected, and the dense packing of the young 

 in the corners seemed to occasion much concern. The masses of fry were con- 

 stantly stirred, as the eggs had been, by a flirt of the fins, which often sent 

 dozens of them .3 or 4 inches upward, to fall back on the pile. 



When the nest is completed, oviposition may take place at once 

 oi" be more or less delayed. In the case of Smith and Harron's fishes — 



Two days intervened between the beginning of the nest making and the laying 

 of the eggs. As soon as the nest was made ready the fish became very quiet. 

 During most of the time they rested on the bottom, with practically no body 

 or fin movement, except at intervals. The fish lay close together, often 

 parallel, with their abdomens just clear of the bottom, their weight being 

 borne on the anal and ventral fins. .\t fre<iuent intervals the female comi)ressed 

 her distended abdomen against the smooth slate bottom with a quivering or 

 convulsive movement, the male often accompanying or following the female 

 in this action, which is obviously for the purpose of loosening the eggs. 



