Family III. Silurid^. 



19 



This species is not recorded south of Santa Rosalia, but may be 

 expected to range as far south as the Rio Panuco. It is one of the 

 largest in the family, reaching a weight of 75 pounds, and is a much- 

 used, excellent food fish. 



Subfamily Pirn elo din ae. 

 Conorhynchus Bleeker. 



Conorhynchus Bleeker, Nederl. Tydschr. Dierk, 102, 1863. (Type, Pimelodus 

 conirosiris Cuvier & Valenciennes.) 



Body elongate, nearly terete anteriorly, compressed posteriorly; snout 

 pointed ; mouth narrow; barbels 6 ; teeth in the upper jaw minute, the lower with 

 very weak teeth or none; no teeth on palate. 



Conorhynchus nelsoni Evermann & Goldsborough. 



Conorhynchus nelsoni Evermann & Goldsborough, Bull. U. S. Fish Comm., 



1902, 140, fig. 1; Rio Usumacinta, Montecristo, Chiapas. 

 Atlantic streams from Chiapas to Brazil. 



CONORHYNCHUS NELSONI Evermann & Goldsborough. 

 No. 50001, U. S. National Museum. 

 Large figure about l A natural size. 

 Small figure, embryo, natural size. 



Head 3J; depth 5; D. 1, 6; A. 17. Body elongate, nearly terete, becoming 

 somewhat compressed posteriorly; head conical, about as wide as deep; a gran- 

 ular saddle over occipital region, extending anteriorly to posterior portion of 

 eye ; a small granular saddle at base of front of dorsal ; f ontanelle long and nar- 

 row, extending an equal distance in front of and behind eye; a narrow transverse 

 bridge equal to diameter of pupil just back of posterior border of eye; snout 

 very long and pointed; mouth small, nearly circular; upper jaw the longer; 

 barbels all very short; maxillary barbel not nearly reaching eye, its length 2 in 

 snout; other barbels shorter; no teeth on vomer and palatines ; teeth on upper jaw 

 confluent in one broad patch, concave posteriorly; teeth in lower jaw very weak; 

 buccal cavity very large; origin of dorsal midway between tip of snout and 

 posterior base of anal; dorsal spine 2 J in head, its upper posterior third roughly 

 serrate; adipose fin large; pectoral spine 2% in head, its posterior edge very 

 strongly serrate; caudal deeply forked, the upper lobe the longer. 



Color light brown above lateral line with bluish reflections, silvery below, 

 becoming pale on the belly; dorsal pale dusky; spine darker in front; inner edge 

 of caudal lobes black. (Evermann & Goldsborough.) 



The male of this species carries the eggs in his mouth during the period of 

 gestation, during which time he is unable to eat any food. This peculiar cus- 

 tom, concerning which but little is known, is practiced by some South American 

 catfishes. 



