288 Fretp Museum or Natura History — Zoétocy, Vor. X. 
maxillary with a few small teeth on its edge; mandible with a single 
series; lateral line incomplete, directed downward and backward; dorsal 
inserted far back; pectorals large; ventrals very small; adipose present. 
35. Thoracocharax maculatus (Steindachner). Paribiba. 
Gasteropelecus maculatus Steindachner, Denkschr. K. Ak. Wiss. Wien, 
XLI, 1879, 168 (Rio Mamoni, Chepo, Panama); Jordan & Ever- 
mann, Bull. U. S. Nat. Mus., XLVII, 1896, 338; Regan, Biol. 
Cent. Amer., Pisces, 1908, 173. 
Head 3.35 to 4; depth 1.7 to 1.9; D. roor 11; A. 33 to 36; scales 30to 35. 
Body deep, strongly compressed; the dorsal profile straight over 
eyes, but slightly convex from nape to dorsal; the thoracic region much 
dilated, the abdomen with a sharp keel; head small, flat above; snout 
blunt, 3.4 to 4 in head; eye 3.1 to 4; interorbital 2.1 to 2.45; mouth small, 
nearly vertical; lower jaw projecting; maxillary reaching anterior margin 
of eye; premaxillary teeth in 2 series, the outer series consisting of only 
2 conical teeth, near tip of jaw, the second series with 10 tricuspid teeth; 
maxillary with 4 or 5 pointed teeth on its edge; lower jaw with a single 
series, anteriorly with 8 tricuspid teeth and abruptly smaller ones at 
sides; gill-rakers poorly developed; lateral line incomplete, directed 
downward and backward toward about the third ray of anal, failing to 
reach base of anal by from 3 to 6 scales; scales large along side, reduced 
on abdomen and above base of anal, the rows directed downward and 
backward on lower part of side; dorsal fin small, its origin notably behind 
origin of anal, about midway between margin of preopercle and tip of 
caudal; adipose fin small, just behind vertical from base of last anal 
ray; caudal fin forked, the lobes subequal; anal fin rather long, its base 
equal to depth of body at origin of dorsal; ventral fins not much longer 
than pupil, inserted just in front of vent; pectoral fins large, reaching 
beyond origin of anal, 2 to 2.25 in length of body. 
Color silvery, darker above; sides sometimes with a faint plumbeous 
band; no caudal spot. Chromatophores on scales so arranged as to form 
dotted vertical lines on sides; abdominal keel dusky. Fins unmarked. 
Of this species there are at hand nearly 300 specimens, ranging in 
length from 42 to 92 mm. ‘These were taken near Chorrera, Panama, 
and in the Rio Bayano and Rio Tuyra basins. 
We have for comparison specimens of 7. brevis Eigenmann, from 
Raspadura, Atrato Basin, Colombia. This is certainly a very closely 
related species, if in fact distinct. The two seem to intergrade, but T. 
brevis averages fewer scales in the lateral series and the average depth is 
slightly greater. 
Habitat: Pacific slope of Panama. 
