SOUTH AMERICAN NEMATOGNATHI. 323 



255. Nematogenys inermis. 



Trichomycteriis inermis Gnichenot, in Gay Hist. Chil. Zool. ii, 312, 



pi. ix, fig 2, 1848 (Chile). 

 Nematoyenys inermis Girard, U. S. Nav. & Astroii. Exped. 240, pi. 



xxxii, 1855 (Kio de Maypu near Santiago); Philippi, MB. Ak. 



Berl. 716, 1866 (Chile); Giinther, Cat. v, 272, 1864 (copied); E. & 



E. Proc. Cal. Acad. Sci. 2d Ser. ii, 50, 1889 (Curico; Santiago). 

 Nematoyenys nif/ricans Philippi, 1. c. 716 (Chile). 

 Nematogenys pallidus Philippi, 1. c. 716 (Chile). 

 Habitat: Fresh waters of Central Chile. 



N. nigricans and pallidus seem, to be color varieties of 

 N. inermis. 



Tail compressed, head depressed, the caudal peduncle 

 about as deep as the body. Head entirely covered with 

 soft skin, little longer than wide, its depth l|-2 in its 

 length. Eye small, superior; interocular width little less 

 than length of snout; orbit without a free margin. Mouth 

 wide, terminal, each jaw with a rather deep band of vil- 

 liform teeth. 



Gill-membranes narrowly joined to the isthmus. 



Anterior nasal opening with a barbel which is about 

 1J times as long as the eye; a series of pores extending 

 from it backward below the eye; a prominent pair of 

 pores between the eyes. 



Pectoral pore minute, above and behind the pectoral 

 spine. 



Origin of dorsal fin one-fifth nearer tip of snout than 

 to base of middle caudal rays in specimens .12 metre 

 long; one-fifth nearer base of caudal rays than to tip of 

 snout in a specimen .26 metre long. 



Margin of all the fins rounded. Caudal with numer- 

 ous accessory rays, the middle caudal rays 1-1 J in the 

 head. Origin of ventrals below or slightly behind the 

 first dorsal ray. Inner margin of pectoral spine serrate, 

 its lower surface spiny. 



Light brown mottled with darker, a series of about 5 



