SOUTH AMERICAN NEMATOGNATHI. 335 



266. Pygidium knerii. 



Trk'homycterus knerii Steiudachuer, Ichthyol. Beitr. xii, 21, pi. v, 



fig. 1-la, 1SS2 (Cauelos). 

 Fi/gidium knerii E. & E. Proc. Cal. Acad. Sci. 2d Ser. ii, 52, 1889 



(Cumbaca). 

 Habitat: Eastern slope of Eciiador; Ciimbaca. 



Elongate, compressed; head greatly depressed, flat 

 above; the eyes entirely superior; width of the head less 

 than its length. Barbels scarcely extending beyond the 

 eyes, which are equidistant from tip of snout and end of 

 opercle. A broad band of villiform teeth in each jaw. 



Pectoral rounded, the first ray slightly prolonged. 

 Origin of dorsal above posterior edge of base of ventrals, 

 equidistant from tip of caudal and nares, the last ray 

 over origin of anal. 



Caudal rounded, its distance from the anal 4i in the 

 length. 



Ventrals nearer tip of snout than tip of caudal. 



Uniform brown, darkest on the back. 



Head 5 (5| in total); depth Sf; D. 10; A. 9. 



One specimen .11 m. Cumbaca. Thayer Expedition. 



267. Pygidium dispar. 



Pygidium dixpar Tschudi, Faun. Per. Ichthyol. 22, pi. 3, 1845 

 (Eastern slope of the Peruvian Andes, at an altiti;de of 14,000 

 feet); E. & E. Proc. Cal. Acad. Sci. 2d Ser. ii, 52, 1889 (Callao, 

 Peril). 



Habitat: Eastern and western (?) slopes of the Periivian Andes. 



This species is distinguished by its emarginate caudal 

 and the regularity of its color markings. It is very 

 doubtful whether the male is of uniform color. 



Elongate, compressed, the depth everywhere less than 

 the length of the head. Head longer than wide by more 

 than a diameter of the eye. Eye moderate, 4 in the 

 interocular, equidistant from tip of snout and end of 

 opercle. None of the barbels reaching quite to the gill- 

 opening. Gill-openings continued forward to below the 

 eye. 



