.332 CALIFORNIA ACADEMY OF SCIENCES. 



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 preopercle. Mouth wide, more than one-third 

 the length of the head. 



Pectoral rounded, the first ray prolonged in a short 

 filament, 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 di- 

 vision from the true caudal rays marked. Caudal al- 

 ways rounded, its distance from the anal 4|-4| in the 

 length. 



Color of largest specimens dark reddish brown, sides 

 with fine white or silvery spots and vermiculatioiis. Spec- 

 imens from .10-.20 m. greatly variable, grayish or dark 

 brown, with darker markings; sometimes the ground 

 color predominating, sometimes only forming reticula- 

 tions between the dark markings; young with an inter- 

 rupted dark band along the sides. 



Head 4J-5J (5J-6| in the total); depth 3J-6J; D. 13; 

 A. 11. 



More than one hundred specimens .03-. 35 in. Cusco, 

 Moho and Puno on Lake Titicaca. Garmaii and Kand. 



261. Pygidium brasiliensis. 



Trichomycterus brasiliensis Keiuhardt, MS. Liitken, Overs. Daii. 



Selsk. 1873, No. 3, 29 (Rio das Velhas); id. Velhas Flodeiis 



Fiske 135 and i, pi. iii, fig. 8, 1875 (Rio das Velhas). 

 Pygidium brasiliensis E. & E. Proc. Cal. Acad. Sci. 2d Ser. ii, 51, 



1889 (Rio Parahyba; Mendez; Lagoa Santa; Santa Cruz). 

 ? Trichomy clems brasiliensis tristis Liitkeu 1. c. 137 and i, 1875 (Rio 



das Vellms. 

 Habitat: Rio Janeiro to Rio San Francisco. 



Elongate, compressed backward. Head greatly de- 



