AMERICAN CATFISHES. 17 



two of which were unmistakably the parents of the brood, for the reason that they 

 did not permit the third one to approach near the mass of eggs, which one of them 

 was watching vigilantly. One of the individuals remained constantly over the 

 eggs, agitating the water over them with its anal, ventral, and pectoral fins. This 

 one subsequently proved to be the male, not the female, as was at first supposed. 

 The female, after the eggs were laid, seemed to take no further interest in them, the 

 whole duty of renewing and forcing the water through the mass of adherent ova devolv- 

 ing upon the male, who was most assiduous in this duty until the young had escaped 

 from the egg membranes. During all this time, or about a week, the male was never 

 seen to abandon his post, nor did it seem that he much cared even afterwards to leave 

 the scene where he had so faithfully labored to bring forth from the eggs the brood 

 left in his charge by his apparently careless spouse. The male measured 15 inches 

 in length, the female one-fourth inch more. 



The mass of ova deposited by the female in a corner and at one end of the slate 

 bottom of the aquarium measured about 8 inches in length and 4 inches in width, 

 and was nowhere much over one-half to three-fourths of an inch in thickness. The 

 ova were covered over with an adhesive, but not gelatinous, outer envelope, so that 

 they were adherent to the bottom of the aquarium and to each other where their 

 spherical surfaces came in contact, and consequently had intervening spaces for the 

 free 'passage of water, such as would be found in a submerged pile of shot or other 

 spherical bodies. It was evident that the male was forcing fresh water through this 

 mass by hovering over it and vibrating the anal, ventral, and pectoral fins rapidly. 

 There were probably 2,000 ova in the whole mass, as nearly as could be estimated. 

 All of those left in the care of the male came out, while one-half of the mass which 

 he had detached from the bottom of the aquarium on the third day, during some of 

 his vigorous efforts at changing the water, were transferred to another aquarium, 

 supplied with running water, and left to themselves. Those which were hatched 

 by the artificial means just described did not come out as well as those under natural 

 conditions. Nearly one-half failed to hatch, apparently because they were not 

 agitated so as to force fresh water among them and kept clean by the attention of 

 the male parent. * * * When first hatched, on the sixth to eighth day, the young 

 exhibited a tendency to bank up or school together like young salmon. They also, 

 like young salmon, tended to face or swim against the current in the aquarium, a habit 

 common, in fact, to most young fishes recently hatched. * * * 



On the fifteenth day after oviposture it was found that they would feed. While 

 debating what we should provide for them, Mr. J. E. Brown threw some pieces of 

 fresh liver into the aquarium, which they devoured with avidity. It was now evi- 

 dent that they were provided with teeth, as they would pull and tug at the fragments 

 of liver with the most dogged perseverance and apparent ferocity. This experiment 

 showed that the right kind of food had been supplied, and, as they have up to this 

 time (August) been fed upon nothing else, without our losing a single one, nothing 

 more seems to be required with which to feed them. 



It is worthy of note that when pieces of liver were thrown into the aquarium the 

 parent fishes would apparently often swallow them, with numbers of young ones 

 eating at and hanging to the fragments. I was soon agreeably surprised to find that 

 the parent fishes seemed to swallow only the meat, and that they invariably ejected 

 the young fish from the mouth quite uninjured, the parent fish seeming to be able to 

 discriminate instinctively, before deglutition occurred, between what were its proper 

 food and what were its own young. As soon as the young began to feed they com- 

 menced to disperse through the water and all parts of the aquarium, and to manifest 

 less desire to congregate in schools near the male, who also abated his habit of fanning 

 the young with his fins, as was his wont during the early phases of development. 



45738°— 10 3 



