154 MEMOIRS OF THE CARNEGIE MUSEUM. 



minute yellowish dots; lips, the openings of the mucous canals in mid-dorsal region, 

 the anus, and a small spot at origin of caudal, yellowish; fins hyaline. 

 Distribution: Essequibo basin, British Guiana. 



25. Porotergus gunbeli sp. nov.^ (Plate XXIII, fig. 3.) 



Porotergus gimbeli Ellis, in Eigenmann, Freshwater Fishes of British Guiana. 

 Mem. Carnegie Mus., Vol. V, 1912, 441. 



3197 C. M., type, 200 mm. Para, Jan. 22, 1910, Haseman. 



3198 C. M., cotypes, two, 170-240 mm. Para, Jan. 22, 1910, Haseman. 

 Cotype, one. Hubabu Creek, B. G., Oct. 1, 1910, Ellis. 



Head 8.5 to 10.25; greatest depth of the body 8.25 to 9 in the length to the 

 base of the caudal; anal rays, type, 175; cotypes, 178, 167, 180. 



Snout 3 to 3.6, interorbital 4 to 5 in the head; eye 3 to 3.5 in the snout, 2 to 2.8 

 in the interorbital and 11 to 14 in the head; lateral line prominent, extending out 

 on the caudal. Snout rather short and blunt; mouth moderately large; jaws equal 

 when closed; the lower included; teeth small, conical and few in each jaw; eyes 

 small. 



Body and head compressed, body rather elongate; width of the head 2.5 to 3.1, 

 depth of the head in the occipital region 1.3 to 1.6 in the greatest depth of the 

 body; anus on the vertical from the eye; scales moderately large and prominent; 

 a mid-dorsal band extending to the end of the dorsal filament with numerous 

 mucous pores and without scales; dorsal profile very weakly convex or almost 

 straight; ventral profile somewhat convex. 



Caudal fin 1.8 to 2.5, pectorals 1.2 to 1.5 in the head; origin of the anal the 

 diameter of the eye or a little more in front of the vertical from the gill-opening; 

 scales extending well out on the caudal. 



Ground-color rather light yellowish brown; dorsal portions, especially the 

 naked dorsal band, overlaid with dark brown; most of the scales somewhat outlined 

 with brown; ventral parts lighter; a series of oblique blackish brown stripes alter- 

 nating with the anal rays extending dorsad from the edge of the anal base about 

 half way to the lateral line; mouths of the mucous pores and the under parts of 

 the head a clear, pale yellow or buff; anal hyaline; pectorals hyaline to dusky, the 

 first two or three rays usually distinctly brown; caudal base whitish, the scaled 

 portion of the caudal almost black, the outer margin hyaline. 



Distribution: Lower Amazon and British Guiana. 



A specimen. No. 2972, from Santarem, 190 mm., with head 7.5, snout 3; A. 

 175, probably belongs here. 



' Named for Mr. Jake Gimbcl, whose generosity made the Gimbel Expedition to Britisli Guiana possible. 



