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 balenops (Cope). 
Sternarchus balanops Corn, Proc. Am. Philos. Soc., 1878, 682 (Peruvian Amazon) ; 
HIGENMANN AND KIGENMANN, Proc. U. 8. Nat. Mus., XIV, 1891, 62. 
Sternarchella balanops K1GENMANN AND Warp, Proc. Wash. Acad. Sci., VII, 1905, 
164 (Peruvian Amazon); E1aggnMANN, Repts. Princeton Univ. Exp. Pata- 
gonia, IIT, 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. Seales very large, in only nine longitudinal rows at the 
base of the dorsal thong. Color olivaccous, 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 
seales.”” (After Cope.) 
XIV. Pororereus Ellis. 
Porotergus Wits, in Kigenmann, Freshwater Vishes of British Guiana. Mem. 
Carnegie Mus., V, 1912, 440. 
Type, Porotergus gymnotus Fllis. 
Distinguished from the other Sternarchinw by the absence of seales along the 
middle of the baek 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. 
Spwcrus OV Pororeraus. 
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, 
gumnotus, 
ad. Mead 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. 
