240 Field Museum of Natural History — Zoology, Vol. X. 



Body elongate; mouth terminal or with lower jaw the shorter; jaws 

 with villiform teeth; no teeth on vomer or palate; nostrils remote from 

 each other; no nasal barbels; barbels 6; occipital process small or want- 

 ing, not reaching the dorsal plate; eye with a free orbital margin; dorsal 

 fiin with I slender spine and 5 to 8 branched rays; adipose fin long, adnate 

 to the back. To this genus belongs a large number of fresh-water cat- 

 fishes, inhabiting streams from southern Mexico to Peru and the Rio de 

 la Plata. One species only occurs in the Panama Canal Zone region. 



1. Rhamdia wagneri (Gunther). 



Pimelodus cinerascens (non Gunther) Kner & Steindachner, Abhandl. 



K. Bayer. Ak. Wiss. Miinchen, 1865, 49 (Panama). 

 Pimelodus wagneri Gunther, Trans, Zool. Soc. London, 1868, 474 



(Atlantic and Pacific rivers of Panama) ; Steindachner, Denkschr. 



K. Ak. Wiss. Wien, XLI, 1879 (Rio Mamoni, Chepo, Panama). 

 Rhamdia bransfordi Gill, Proc. Ac. Nat. Sci. Phila., 1876, 337 (Panama). 

 Rhamdia wagneri Eigenmann & Eigenmann, Occ. Pap. Cal. Ac. Sci. I, 



1890, 133 (Gorgona, Rio Chagres; Rio Obispo, Panama; Turbo, 



Atlantic coast. Cent. America); Jordan & Evermann, Bull. U. S. 



Nat. Mus., XLVII, 1896, 151; Regan, Biol. Cent. Amer., Pisces, 



1907, 131 (Shirures, Costa Rica; western Ecuador). 



Head 3.6 to 4.55; depth 5.1 to 6.55; D. I, 6; A. 11 to 13. 



Body elongate, compressed posteriorly; head depressed; profile 

 gently elevated anteriorly, nearly straight; snout broad, its length 2.25 

 to 2.5 in head; eye 5.45 to 7.5; interorbital 2.4 to 2.94; mouth broad, its 

 width greater than length of snout; the upper jaw a Httle in advance of 

 the lower; maxillary barbels varying considerably in length, reaching 

 opposite base of ventrals to opposite or past base of anal; teeth in the 

 jaws in villiform bands; none on palatines or vomer; head covered with 

 skin; occipital process narrow, not extending to the small dorsal plate; 

 fontanel long and narrow, extending past anterior margin of eye; dorsal 

 fin with a poorly developed spine; origin of dorsal not quite half as far 

 from tip of snout as from base of caudal; adipose fin notably longer 

 than head, its base 2.65 to 3.3 in body; caudal fin forked, the lower lobe 

 the larger, rounded; anal fin short, its origin somewhat nearer base of 

 caudal than base of pectorals; ventral fins inserted behind vertical from 

 base of last dorsal ray, failing to reach origin of anal ; pectoral fins rather 

 short, the spine rather weak, and without barbs except in young, its 

 length 1.8 to 2.45 in head. 



Color bluish black above, pale below; sides yellowish green and with 

 a single dark band in young. Dorsal fin with a dark band across middle 

 and a lighter one below it. 



