eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 501 



Head 3+ ; depth 2.25-3; D. XII-XIV,11 or 12; A. 111,7 or 8; lateral line 

 18-19 -f 13-16; scales 29-30 in a median series; eye 3.5 in the head, 1.3 in the 

 preorbital, 1 in the interorbital in the largest; eye in posterior half of the head in 

 the young. 



Dorsal profile steep, the back arched; ventral profile but slightly arched; 

 maxillary-premaxillary border 3.5 in the head; maxillary reaching a little beyond 

 the posterior nares, which are half-way between the tip of the snout and the eye. 

 Lower lip with a frenum; depth of caudal peduncle 1.25 in its length. Gill-rakers 

 11, the upper two at the base of the lobe. 



Cheeks with about six series of scales; preopercle naked; one scale between 

 the lateral line and the dorsal. Base of caudal scaled, fins otherwise naked. 



Dorsal spines subequal from the third, the last a little more than half the length 

 of the head; dorsal sometimes prolonged beyond the caudal; caudal emarginate, 

 its outer rays prolonged; pectoral longer than the head. 



A narrow dark bar from the nape through the eye to the angle of the preopercle ; 

 a black spot near the middle of the sides; a black spot on the anterior dorsal spines; 

 dorsal, caudal, and anal with hyaline spots. 



Biotodoma Eigenmann and Kennedy. 

 Mesops GtJNTHER, Catalogue, IV, 1862, 311 (cupido), preoccupied. 

 Biotodoma Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903, 533. 



Type, Geophagus cupido Heckel. 



Upper gill-arch with a downward projecting lobe, carrying the gill-rakers at 

 its margin; upper lateral line well separated from the dorsal; lateral line not forked 

 on the caudal; preorbital about equal to the eye in the adult. 



340. Biotodoma cupido (Heckel). 



Geophagus cupido Heckel, Ann. Wiener Mus., II, 1840, 399 (Rio Negro; Rio 



Guapore). — Cope, Proc. Am. Philos. Soc, XVII, 1878, 697 (Peruvian Amazon). 



-Pellegrin, "Cichlides," 153, in Mem. Soc, Zool. France, XVI, 1903, 189 



(Obidos; Manaos; Tonantins). — Regan, Ann. and Mag. Nat. Hist., (7), XVII, 



1906, 54 (Essequibo; Tonantins). — von Ihering, Rev. Mus. Paulista, VII, 



1907, 317. 



Mesops cupido Gunther, Catalogue, IV, 1862, 311 (Rio Negro; Guapore). 



Geophagus (Mesops) cupido Steindachner, "Chromidcn Amazonenstromes," 1875, 

 47 (Amazon, near Teffe; Coary; Cudajas; Lake Hyanuary; Rio Negro; Gua- 

 pore; lea; Hyutay; Sambaia; Jatuarana). — Eigenmann and Eigenmann, 

 Proc. U. S. Nat. Mus., XIV, 1891, 70 (name only).— Pellegrin, Bull. Mus. 



