Dec. 28, 1916. Fishes of Panama — Meek and Hildebrand. 263 



Body depressed; anterior profile straight or gently convex; head 

 without ridges; snout not produced, broadly obtuse, its margin granu- 

 lar, with short bristles on sides in male, its length 1.7 to 1.8 in head; eye 

 without orbital notch, 6.5 to 8.7; interorbital 3,1 to 3.6; lips reverted, 

 papillose; maxillary barbel shorter than eye; predorsal plates 3, without 

 carinations; lateral keels anteriorly obscure or wanting, coalesced on 

 15th or 1 6th scute; 17 or 18 scutes from anal to base of caudal; s to 8 

 rows of small plates on belly between lateral series; dorsal fin anteriorly 

 not greatly elevated, not much longer than head, its origin over base of 

 ventrals; caudal fin forked, the outer ray of both lobes produced, the 

 upper one bearing a filament; anal fin anteriorly moderately elevated, 

 the spine somewhat shorter than head; ventral fins reaching to or a 

 little past origin of anal; pectoral fins reaching a Httle beyond base of 

 ventrals, i.o$ to 1.23 in head. 



Color dark grayish brown, with obscure darker blotches above; 

 pale below. Fins usually with indistinct dark markings. 



This species is represented by many specimens, ranging from 40 to 

 250 mm. in length. This fish was foimd only in the Rio Bayano and 

 Rio Tuyra basins. It is rare in the former but abundant in the latter. 



This species is rather closely related to O. tamancB Regan, from which 

 it differs in having from 5 to 8 longitudinal rows of plates on belly 

 between the lateral series, instead of only 3. The snout in the present 

 species is more obtuse and the fins are lower. 



Family III. Callichthyidae. 



Sides with 2 series of lateral scutes; mouth terminal, lower lip not 

 reverted; air bladder vestigiary, one on each side of the coalesced verte- 

 brae and entirely surrounded by a bony capsule, the cavity communicat- 

 ing with the exterior by means of a long narrow slit in the temporal 

 plate. Caudal vertebrae normal, the neiural and haemal spines spine- 

 like, separated from each other. 



13. Genus Hoplosternum Gill . 



Hoplosternum Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 395 (type 

 Callichthys IcBvigatus Yalenciennes = Callichthys littoralis Hancock). 

 Body with 2 lateral series of scutes, overlapping along median line, 

 forming a depression; gill-membranes confluent with the skin of the 

 isthmus; two pairs of nuchal plates between htimeral and coracoid 

 process; coracoids exposed; 2 pairs of maxillary barbels; no mandibular 



