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



groove at nape; snout broad, 3.5 to 4.3 in head; eye 3.4 to 4; mouth wide; 

 jaws weak; gill-rakers very short; lateral line straight, slightly above the 

 middle of side; scales large, regularly placed, with a serrate membranous 

 border, 1 1 or 1 2 on median line in advance of dorsal ; dorsal fin inserted 

 midway between tip of snout and tip of adipose or slightly nearer the 

 latter; caudal forked, the lobes with small scales at base; anal fin with 

 concave margin, the anterior rays reaching far beyond tips of posterior 

 rays when deflexed; ventral fins inserted under the base of dorsal; 

 pectoral fins a Httle shorter than the ventrals, 1.4 to 1.8 in head. 



Color plain brassy, darker above than below; no distinct markings 

 on body or fins. 



The Panama collection contains 263 specimens, ranging in length 

 from 75 to 200 mm. These were taken at the following localities: a. 

 Rio Chorrera Basin, at Chorrera and a small creek near Chorrera. 

 b. Rio Marte Arnade. c. Rio Abaco. d. Rio Juan Diaz. e. Rio 

 Bayano Basin, at El Capitan, Chepo, and Rio Calobre. f. Rio Tuyra 

 Basin, at mouth of Rio Yape, Rio Capete, Rio Cupe at Boca de Cupe, 

 Rio Aruza at Aruza, Rio Cituro at Cituro, Rio Setiganti at Cana, Rio 

 Grande near Cana. The above includes all of the river basins visited 

 on the Pacific slope of Panama, except the Rio Chame and the Rio 

 Grande. The latter lies almost wholly within the Canal Zone and had 

 at the time of our visit already been much disturbed by the construction 

 of the Canal. There is little doubt but that this fish occurred there 

 before the digging of the Canal, as it is abundant in streams on both 

 sides of it. 



This fish was not found by us where there was much current, but 

 it occurred most commonly in quiet pools and often in stagnant ponds. 

 It is common in streams at the head of tide water. The highest eleva- 

 tion at which it was taken was at Cana in the upper Rio Tuyra Basin. 



We have specimens for comparison from the Atlantic slope of 

 Colombia. No differences are apparent, except that the Panama 

 specimens appear to be somewhat darker in color. 



Habitat: Pacific slope of Panama, Atrato and Magdalena basins and 

 Lake Maracaibo. 



17. Genus Apareiodon Eigenmann. 



Apareiodon Eigenmann, Ann. Carnegie Mus., X, 1915 (1916), 71 (type 



Parodon piracidbcB Eigenmann). 



Small fishes with elongate, little compressed body; ventral surface 

 flattish; head small; snout pointed; mouth inferior, a transverse slit; 

 lower jaw scoop-shaped, the lip with a straight transverse margin 



