350 MEMOIRS OF THE CARNEGIE MUSEUM. 



1. Pseudostegophilus nemurus (Giinther). (Plate XLIV, fig. 5.) 



Stegophilus nemurus Gltnther, Proc. Zool. Soc, London, 1869, p. 429. (Peruvian 



Amazon.) 

 Pseudostegophilus nemurus Eigenmann & Eigenmann, Proc. Cal. Acad. Sci. (2), 



II, 1S89, p. 54 (Maranon or Ucayale); Occasional Papers Cal. Acad., Sci. I, 



1890, p. 341; Proc. U. S. Nat, Mus., XIV, 1891, p. 37; Eigenmann, Reports 



Princeton Univ. Exped. Patagonia, III, 1910, p. 400. 



Habitat. — Upper Amazon, Rio Mamore. 

 7547a-/, C. M., 63-78 mm. Rio Mamore. Sept, 19, 1909. J. D. Haseman. 



Head 5; depth 6-6.5; D. 9; A. 7; P. 6; eye 4-4.5 in the head, less than snout or 

 interorbital ; maxillary barbel about as long as the eye, lower barbel very minute. 

 Five rows of teeth on the upper lip, four in the upper jaw, six rows in the lower jaw 

 and lip; gill-membrane not forming a fold across the isthmus; eight or nine spines 

 on the interopercle and opercle; pectoral a little shorter than the head; origin of 

 ventrals about equidistant from tip of snout and tip of middle caudal ray (its base 

 in a specimen in the Mus. Comp. Zool.) ; origin of anal behind the dorsal, the dis- 

 tance of the base of its last ray from the base of the middle caudal ray four and one- 

 half in the length; caudal deeply forked, the lobes pointed, the upper lobe longer 

 than the lower; distance of origin of dorsal from base of middle caudal rays 1.5-1.6 

 in its distance from the snout; a dark shade across the head between the eyes, 

 another between the opercles, four bands across the back and sides about equal to 

 the interspaces, the margins of the bands darkest; lower caudal lobe and tip of the 

 upper black. 



Genus IX. Homodicetus 34 Eigenmann & Ward. (Plate XXXVII.) 



Homodicetus Eigenmann & Ward, Annals Carnegie Mus., IV, 1907, p. 117, pi. 

 XXXIV, figs. 2 and 3 (anisitsi). 

 Type. — Homodicetus anisitsi Eigenmann & Ward. 



Opercle with four or five spines directed upward and backward, interopercle 

 with more, directed downward and backward; eye 3.5-5 in the head. Otherwise 

 like Henonemus. 



Key to the Species of Homodletus. 

 a. Caudal slightly emarginate, oblique; accessory rays numerous; origin of dorsal equidistant from tip of 

 caudal and eye; origin of ventrals equidistant from snout and caudal; D. S; A. 8; back and sides 

 with chromatophores, hut without distinct spots; middle caudal rays black. 



1. anisitsi Eigenmann & Ward. 



34 o/jioSimTos = living or eating with others. In allusion to the known parasitic habits of some of its 

 relatives. 



