SOUTH AMERICAN NEMATOGNATHI. 337 



269. Pygidium pardum. 



Trirhomii<:terus. pardus Cope, Proc. Acad. Nat. Sci. Philad. 1874, 

 132 (loc.?); id. Proc. Am. Philos. Soc. 1877, 45 (Jequetepeque; 

 Callao Bay). 



Pi/gldhun pardum Eigenm. & Eigeum. Proc. Cal. Acad., 2d Ser. ii, 

 52, 1889. 



Habitat: Callao Bay. 



270. Pygidium immaculatum. 



Pygidium immacnlatuin Eigeum. & Eigeum. Proc. Cal. Acad. 2d Ser. 



ii, 1889 (Juizde Fora; Sao Matheos; Goyaz). 

 Habitat: East-ceutral Brazil. 



Fourteen specimens .06-. 20 m. Juiz de Fora; Sao 

 Matheos; Goyaz. 



A specimen from Macacos may be a variety of this 

 species. 



This may be the male of P. brasiliensis. The reproduc- 

 tive organs are, however, all empty as after spawning, so 

 that it would be difficult to separate male from female, 

 after they had been in alcohol twenty-five years. If it 

 is a species distinct from brasiliensis it must breed earlier 

 than that species, as most of our specimens of P. brasil- 

 iensis are ripe females. 



Elongate, compressed backward; head gently depressed, 

 the snout broad, spatulate; width of the head less than 

 its length. Eye comparatively large, equidistant from 

 tip of snout and tip of opercle. Barbels all rather short; 

 the nasals scarcely reaching occiput or shorter; maxilla- 

 ries not to gill-opening. Gill-opening continued forward 

 to below the eye; the membrane with a free margin 

 across the isthmus. 



Pectorals rather short and broad, the first ray pro- 

 longed in a filament. 



Dorsal truncate, its last ray in front of the anal, its 

 origin equidistant from tip of caudal and base of nasal 

 barbel or slightly nearer tip of caudal. 



Caudal broad, emarginate, the upper lobe sometimes 

 produced; its distance from the anal 5h in the length. 

 22 



