6 FISHES OF WESTERN SOUTH AMERICA 
Of nearly uniform depth from occiput to anal. Pores of head inconspicuous, 
not aggregated; a small fontanel at base of occipital process; premaxillary band of 
teeth very little wider at sides than at middle; outer mental barbels extending to 
about middle of pectorals; dorsal a little higher than long; caudal deeply cleft, but 
not to its base, the lower lobe much the broader; pectoral spine nearly half as long 
as the head. 
Uniform ash color; a series of translucent areas near basal portion of dorsal. 
This species differs from the R. humilis of Giinther in ways pointed out by Cope 
long ago, and by Fowler. 
26. RHAMDIA PENTLANDI (Cuvier and Valenciennes) 
Pimelodus pentlandi Cuvier and Valenciennes, 1840, Hist. Nat. Poiss., XV, 183, pl. 435, tributaries 
of Lake Titicaca; 
Steindachner, 1876, Sitzb. KKIx. Akad. Wiss. Wien, LX XIV, 48 (reprint page), Monterico, 
Tulumayo; 
Steindachner, 1882 (1883), Denksch. KIx. Akad. Wiss. Wien, XLVI, 25 (reprint page), Rio 
de Huambo. 
Rhamdia pentlandi Eigenmann and Eigenmann, 1888, (2), I, 126; 
Eigenmann and Eigenmann, 1890, Oce. Papers Cal. Acad. Sci., I, 127; 
Kigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 386. 
Peruvian Andes 
Its occurrence in a tributary of Lake Titicaca seems very questionable, as well 
as the identity of Steindachner’s material from northern-central Peru with that 
collected in the South by Pentland. 
Native name Auntsche applied to this species (Steindachner). 
27. RHAMDIA DORSALIS Gill 
Rhamdia dorsalis Gill, 1870, Proc. Acad. Nat. Sei. Phila., X XII, 94, Maranon or Napo basin; 
EKigenmann and Higenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 135; 
Kigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 386. 
Oriental Peru or Ecuador; known only from the types 
Genus 11: IMPARFINIS Eigenmann and Norris 
Imparfinis Eigenmann and Norris, 1900, Revista Mus. Paulista, IV, 351. 
Type: Imparfinis piperatus Eigenmann and Norris 
Southeastern Brazil to Upper Maranon 
A genus of doubtful validity. ‘Cheeks to opercle covered with thin skin; 
head depressed; anal short; dorsal spine not pungent; eye small, without free 
margin.’ (Gosline). 
