326 CALIFORNIA ACADEMY OF SCIENCES. 



256.3. TrichomycteriLS may'moratus Philippi, 1. c. 714. 

 Blackish gray, marbled with many black spots, as inpunc- 

 tatus; fins dark. Depth lOyy; D. 10; A. 6. 



256.4. Trichomydenis tenuis AYeyenbergh, Actas 

 Acad. Nac. Cienc. Exactas, iii, 12, pi. iii, Buenos Aires, 

 1877 (Sierra de Cordoba, near Cruz-del-eje). Yellow, eyes 

 and barbels black; head triangular; opercle and preop- 

 ercl well armed. Body much compressed. D. 6; A. 5. 



256.5. Trichomycterus corduvensis Weyenbergh, 1. c. 

 11, pi. iii (Rio Primero). Obscure blotches on the back, 

 the sides with a dusky band. 



256.6. Trichomycterus tigrinum Philippi, 1. c. Light 

 with reddish points; fins immaculate. Head 6|; depth 

 6| in total length. D. 9 or 10; A. 6. 



256.7. Pygidiuvi poeyanuiii. 



Trichomycterus rivulatus Cope, Proc. Acad. Sci. Philad. 

 1874, 132 (Arequipa, Peru); not of Cuv. & Val. Trich- 

 om,ycteru8 poeyanus Cope, Proc. Am. Philos. Soc. 1877, 

 47. Pygidium poeyaniim E. & E. Proc. Cal. Acad. Sci. 

 2d Ser. ii, 50, 1889. 



Habitat: Western slopes of southern Peru. 



ANALYSIS OF THE SPECIES OF PYGIDIUM.* 



n. Origin of dorsal iu front of the origin of the anal. 



h. Dorsal rays 15-21; first pectoral ray not produced in a filament; gill- 

 merabraues joined to the isthmus. 



c. D. 21; origin of dorsal equidistant from occiput and tip of caudal. 

 Anal inserted below the 9th dorsal ray and terminating under the 

 17th. macrcei 257. 



cc. D. 15; origin of dorsal equidistant from tip of snout and tip of 

 caudal; last ray of the anal under last ray of the dorsal. Distance 

 of anal from base of caudal 3| in the length. maculatum 258. 



hb. Dorsal rays less than 15. 



d. None of the dorsal rays prolonged, 

 e. Dorsal placed partly over the anal. 



* Iu the species examined by us the rudimentary rays of the dorsal and anal are 

 counted. 



