ate Ss. 
Dec. 28, 1916. FisHes or PANAMA— MEEK AND HILDEBRAND. 245 
firmly joined to the dorsal plate; humeral process wanting; gill-mem- 
branes joined to the isthmus; dorsal fin with a rather weak spine and 6 
or 7 rays, its origin in advance of ventrals; adipose fin very short; anal 
fin long. 
5. Ageneiosus caucanus Steindachner. 
Ageneiosus caucanus Steindachner, Denkschr. K. Ak. Wiss. Wien, 
XLI, 1880, 61, Pl. VI, figs. 1 & 2 (Rio Cauca); Eigenmann & 
Eigenmann, Occ. Pap. Cal. Ac. Sci., I, 1890, 306. 
Head 3.5 to 3.8; depth 6.1 to 7.45; D. I, 6; A. 32 to 40. 
Body elongate, compressed; profile from snout to dorsal deeply con- 
cave in large males, only slightly concave in females; head low; snout 
very broad, much depressed, its length 1.77 to 2 in head; eye small, 
lateral, covered by a membrane, 5 to 10 in head; interorbital width 1.88 
to 2.46; mouth wide, its width greater than length of snout; a pair of 
maxillary barbels present, very small in the female; with a stiff bone, 
extending to or beyond angle of mouth in the male; teeth in villiform 
bands, the one in upper jaw about as wide as eye, none on vomer or 
palatines; upper surface of head with a few rather prominent ridges and 
striations, covered with thin skin; a long narrow frontal fontanel; dorsal 
spine in the female rather weak and shorter than snout, much longer in 
the male, and with strongly developed barbs on its anterior side; origin 
of dorsal not much behind base of pectorals, a little more than half as 
far from tip of snout as from tip of adipose; adipose fin small, its base 
not longer than eye, over posterior fifth of anal; caudal fin forked, the 
lobes of about equal length; anal fin long, its base equal to or longer than 
head, the spine much more strongly developed in the male than in the 
female; ventral fins usually not quite reaching origin of anal; pectoral 
fins failing to reach ventrals, the spine 1.93 to 2.25 in head. 
Color yellowish creamy. The back in some specimens uniform 
bluish black. In others this color is broken up into stripes, or blotches. 
Sides with dark spots varying notably in size among the individuals. 
There is usually a series of spots forming a row from just above angle of 
gill-opening backward. Dorsal fin usually with dark spots. Caudal 
fin with a dark longitudinal bar on its upper lobe and a single blotch on 
the lower lobe. In very large examples both lobes bear several dark 
blotches, but no definite bar. Anal and ventrals unmarked; pectorals 
with or without a few dark blotches. 
There are 45 specimens of this species in the Panama collection. 
They range from 130 to 460 mm. in length. All are from the lower Rio 
Tuyra, some of them from below the head of tide water and others 
from as far up as Boca de Cupe. 
