EIGENMANN: THE PYGIDIID.E, A FAMILY OP SOUTH AMERICAN CATFISHES. 267 



urethral of aquatic mammals and of large fishes. Further study may demonstrate 

 that some species of Candiriis have become parasitic in the bladders of large fishes 

 and aquatic mammals. These are all questions that may legitimately be taken 

 up by future expeditions. 



The first of the commensals or parasites of this family to be described is the 

 Stegophilus insidiosus of Reinhardt. Reinhardt secured all of his specimens from 

 the gills of the giant catfish of the Rio das Velhas, a tributary of the Rio San Fran- 

 cisco. Haseman secured one specimen of this fish from the sandy island opposite 

 Januaria, near the mouth of the Rio San Francisco. The fish therefore may and 

 does live in the open as well as in the gill-cavities of larger fishes. 



The account of Stegophilus insidiosus Reinhardt, given by the author of the 

 genus and species, which was published in 1858 (Cf. Naturhistorisk Forenings 

 Videnskabelige Meddelelser, Copenhagen, 1858, reprint, pp. 1-19, PI. II) possesses 

 great interest. Professor Reinhardt having been repeatedly informed that a large 

 species of catfish, belonging to the genus Pseudolatystomus and known by the natives 

 as Sorubim, protects its young by carrying them in its gills, determined, if possible, 

 to verify the statement. An English translation of a portion of his narrative is here 

 given : 



It deeply interested me to ascertain with exactness the circumstances under which this pecu- 

 liar method of protection takes place, and also to examine the young at the time when they make 

 use of it. I therefore offered the fishermen in the vicinity of Lagoa Santa, where I was staying at 

 the time, a good sum if they would bring me a Sorubim with some of its young in the gill-cavities. 

 Finally on February 27, 1852, a fisherman brought me one, in the gills of which he said there 

 should be a little "young one." On examination I indeed found there a young fish, hardly an 

 inch long, which was already dead, although the Sorubim still showed faint signs of life. The 

 little fish looked so unlike the big one that I was astonished, and upon finding out that the old 

 fish was a male I was strengthened in my doubt as to their relationship. When the same fisher- 

 man two clays later again brought a male Sorubim with a young one, which looked exactly like 

 the first, but was about three times longer, it became clear to me that these two small fishes 

 could in no wise be what it was claimed they were. On the other hand they recalled to me the 

 picture I carried in my mind of a Trichomycterus which I had obtained one year previously from 

 the Rio das Velhas under the name of Cambeja, or Bagre molle. I naturally concluded that the 

 fisherman in order to get the reward offered, had brought me the young of this Cambeja and was 

 passing them off as the young of the Sorubim. I complained to his face about this procedure, 

 and, though I did not obtain any confession from him, I nevertheless had no doubt that I had been 

 made the victim of a swindle. During the few weeks I still remained in Lagoa Santa before start- 

 ing on my homeward journey to Europe, nothing happened to induce me to think otherwise. 



Upon my return home, as soon as I could get access to the literature, and could make a direct 

 comparison between the supposed young of the Sorubim and the Cambeja, I at once saw that I 

 had made a mistake in assuming that the former were the young of the latter. In short these 



