SOUTH AMERICAN NEMATOGNATHI. 169 



teeth very deep, its depth 4 in its width; 

 mandibulary band of teeth at the sym- 

 physis about one-half as wide as the in- \/^ y/ 

 termaxillary band. Gill-rakers 4-|-10. 



Distance of dorsal spine from snout 2i in the length, 

 the spine high and slender, 2 in head; its anterior mar- 

 gin smooth, the posterior margin verrucose. Distance 

 of adipose fin from the dorsal equal to the length of the 

 dorsal. Adipose fin 5^ in the length. 



Pectoral spine about 2 in head, its anterior margin 

 with short blunt teeth, the posterior margin with long 

 teeth. 



Head 3i ; Br. 9-10; D. I, 6; A. 13. 



A single specimen in poor condition .18 m. Goyaz. 



122. Fimelodus albicans. 



Arius albicans Valeucieuues, Voy. d'Orb. pi. iii, fig. 2, 1847. 



Arius albicans Cuv. & Val. Hist. Nat. Poiss. xv, 80, 1840 (Bueuos 



Ayres). 

 Piramutana albicans Gtinther, Annals & Mag. Nat. Hist. 1880, 9 



(Kio Plata). 

 Arius moroti Valenciennes, Voy. d'Orb. 6, 1847 (La Plata). 

 Pimelodus albicans Eigeum. & Eigenm. Proc. Cal. Acad. 2d Ser. 



i, 134, 1888 (La Plata). 

 Habitat: Kio Plata. 



Dr. Giinther is the first to have rediscovered this 

 species. All the specimens referred to albicans by Liitken , 

 Steindachner and others belong to P. clarias. 



As Valenciennes and Giinther state, this species has 

 no teeth on the pterygoids; it always has teeth on the 

 vomer. In the smallest and largest specimens exam- 

 ined they are present on one side only. It is further dis- 

 tinguished by its small eye and depressed head. 



The vomerine teeth are scarcely sufficient to separate 

 this species from Pirtielodus generically. 



Head rather broad, granulose. Eye small 3|-45 in 

 snout, 73-9 in head, 2§-3 in interorbital, 1 in interna- 

 sal space. 



