Oral Gestation in the Gaff-Topsail Catfish, Felichthys Felis. 33 



sion of the sand and impregnated with milt . One of the parent fish then 

 takes the eggs in his mouth. . . . The eggs are carried in this position 

 until the embryo fish are hatched." Whether this is an observation or a 

 conjecture of Stearns's can not be said. However, the statement is 

 very direct and positive. Smith (1907) quotes it as a fact, and it 

 should be noted here that Stearns seems to have been a careful and 

 accurate observer, and that he had Goode's full confidence. 



However, Steindachner (1875), in describing Arius planiceps, a 

 catfish from Panama, found that at the breeding season the innermost 

 edges of the ventral fins of the female are developed so as to form a 

 kind of pocket. He conjectured that the eggs are extruded into 

 this, fertilized by the male, and then taken into his mouth. He found 

 a similar structure on the female of A. kessleri, the male of which is 

 also a mouth brooder. Moreover, two years before this, Day (1873), 

 writing of the Indian genera Arius and Osteogeniosus, had described 

 precisely similar structures and had made an identical surmise. 



The present writer has sought diligently to ascertain the method 

 of transfer in the gaff-topsail catfish, but in vain. The fish are so 

 large that it has not been found practicable to isolate them in pairs, 

 and the water is too muddy at their breeding-grounds in Newport 

 River for any observations to be made in the open. No structures 

 like those described by Steindachner have been noticed on any female 

 examined. The manner of transfer of the eggs in this fish is still a 

 mystery. 



SEX OF THE EGG-CARRIER. 



As has been stated in the preceding pages, and made clear in the 

 article previously referred to (Gudger, 1916), it is always and only 

 the male that carries the eggs. This has been definitely determined 

 for the gaff-topsail by scores of dissections. In this matter Felichthys 

 felis falls in line with all other siluroid buccal incubators on record 

 save one. This one exception probably more apparent than real- 

 is Arius commersonii, a sea catfish found in the brackish waters of 

 southern Brazil. 



Hensel (1870) first made known this interesting habit in this fish 

 and noted that the male is the incubator. Fifteen years later, von 

 Ihering (1885) confirmed Hensel and concluded his note, which is 

 incidental to a geographical article on the Lagoa dos Patos (in which 

 the fish are caught), by saying that it is the female which carries the 

 eggs. In 1888, von Ihering, in a fuller note on the fish, records the 

 finding of eggs in the mouths of both parents, but thinks this excep- 

 tional in the case of the female, while the rule for the male. However, 

 in 1896, he again notes that both parents incubate the eggs. 



In the section of this paper on feeding, it will be shown that the 

 female gaff-topsail is cannibalistic in tendency, being occasionally 



