152 MEMOIRS OF THE CARNEGIE MUSEUM. 



Ground color pale straw-yellow; mid-dorsal region and top of head quite 

 dark, being almost completely covered with minute black dots, lateral portions of 

 the dorsal region less heavily dotted; sides very sparsely sprinkled with fine dark 

 brown dots; origins of the anal rays faintly outlined with minute spots; cheeks with 

 a very few rather prominent dark brown dots; fin-membranes hyaline, rays more 

 or less brownish. 



This species is found only in the Amazon system. 



23. Sternarchella balaenops (Cope). 



Sternarchus balcenops Cope, Proc. Am. Philos. Soc, 1878, 682 (Peruvian Amazon); 

 EiGENMANN AND EiGENMANN, Proc. U. S. Nat. Mus., XIV, 1891, 62. 



Sternarchella bakenops Eigenmann and Ward, Proc. Wash. Acad. Sci., VII, 1905, 

 164 (Peruvian Amazon); Eigenmann, Repts. Princeton Univ. Exp. Pata- 

 gonia, III, 1910, 448 (Peruvian Amazon). 



"Profile oblique, with a depression between the orbits; snout short and much 

 narrowed; lower jaw large, projecting beyond the upper both anteriorly and 

 laterally, enclosing the latter somewhat as in a whalebone whale. The fissure of 

 the mouth is short, only reaching the vertical line from the anterior nostril. Eyes 

 small, without free border, much nearer the snout than the gill-opening, one-twelfth 

 the length of the head, which latter enters the length without the caudal fin, 8.5 

 times. The depth at the base of the dorsal thong is equal to the length of the 

 head. Anal radii 171. Scales very large, in only nine longitudinal rows at the 

 base of the dorsal thong. Color oUvaceous, with a pale dorsal band which reaches 

 the dorsal thong, and a pale narrow band on each side near the dorsal band. Length 

 165 mm.; length to origin of anal 20 mm.; length to base of dorsal thong 96 mm. 



"This species resembles remotely the S. Schotti of Steindachner, but differs 

 from it and from all the other species in the much enlarged mandible and large 

 scales." (After Cope.) 



XIV. Porotergus Ellis. 



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



Carnegie Mus., V, 1912, 440. 



Type, Porotergus gymnotus Ellis. 



Distinguished from the other Sternarchinai by the absence of scales along the 

 middle of the back to beyond the middle of the dorsal thong; gape rather long, 

 almost reaching vertical from the eye; scales in region of lateral line quite large; 

 body rather elongate. 



Species of Porotergus. 



a. Head 7 to 7.75 in the length to the base of the caudal; snout 2.2 to 2..5 in the head; anal rays 130 to 150. 



gymnotus. 

 aa. Head 8.5 to 10.25 in the length to the base of the caudal; snout 2.5 to 3 in the head; anal rays 175 to 180. 



gimbeli. 



