302 MEMOIRS OF THE CARNEGIE MUSEUM. 



Trichomycterus pentlandi Castelnau, Anim. Noiiv. Am. Sud.,49, pi. XXIV, fig. 1, 



1855 (Lake communicating with the Ucayale). 

 Trichomyctenis pictus Castelnau, Anim. Nouv. Am. 8ud., 59, pi. XXIV, fig. 2, 



1855 (Lake Titicaca). 

 Trichomycterus dispar Gijnther (partim), Cat. Fishes Brit. Mus., V, 273, 1864 

 (Lake Titicaca; Rio de Pontezualo; Andes de la Paz; Guasacona; Rio de Azan- 

 garo); Garman, Bull. Mus. Comp. Zool. Ill, 275, 1875 (Lake Titicaca). 

 ?Pellegrin, Bull. 8oc. Zool. Paris, XXIX, 1904, p. 91; Poissons des Lacs des 

 Hauts Plateaux de I'Am. des Sud., 1907, p. 7 (Lake Titicaca). 

 Trichomycterus pardus Cope, Proc. Acad. Nat. Sci., Phila., 1874, p. 132. 



Habitat. — High Andes of Peru, about Cuzco, Titicaca, Jequetepeque, etc. 

 13833, I. U. M., one, 93 mm. Tirapata, eastern Peru. 13000 ft. From Rosen- 

 berg. 

 13750, I. U. M., one, 145 mm. Ollantaytambo. E. Heller. 



Teeth In about five series in the middle of the jaws, those of the outer series 

 narrow incisors, those of the innermost row conic. 



Head 4.5-5.5; depth 3.75-6.5; D. 13; A. 11. Tail compressed, head depressed, 

 about as wide as long; eye equidistant from tip of snout and end of opercle. Nasal 

 barbels reaching to the posterior margin of the eye, longer in the young. Upper 

 maxillary barbel about to edge of pre-opercle. Mouth wide, more than one-third 

 the length of the head. Pectoral rounded, the first ray prolonged in a short fila- 

 ment, except in the very young. Origin of dorsal equidistant from tip of caudal 

 and a point between occiput and posterior nares, its posterior portion always over 

 the anterior half of the anal. Accessory rays of the caudal very numerous, their 

 division from the true caudal rays marked. Caudal always rounded, its distance 

 from the anal 4.5-4.4 in the length. Color of largest specimens dark reddish brown, 

 sides with fine white or silvery spots and vermiculations. Specimens from 100- 

 200 mm. greatly variable, grayish or dark brown, with darker markings; sometimes 

 the ground color predominating, sometimes only forming reticulations between the 

 dark markings; young with an interrupted dark band along the sides. 



18. Pygidium poeyanum (Cope). 



Trichomycterus rivulatus Cope {non Cuvier & Valenciennes), Proc. Acad. Nat. Sci. 



Phila., 1874, p. 132 (Arequipa). 

 Trichomycterus poeyanus Cope, Proc. Am. Philos. Soc, 1877, p. 47. 

 Pygidium poeyanum Eigenmann & Eigenmann, Proc. Cal. Acad. Sci. (2), II, 1889, 



p. 50; Occasional Papers Cal. Acad. Sci., I, 1890, p. 326; Proc. U. S. Nat. Mus., 



