304 FISHES OF WESTERN SOUTH AMERICA 
Fowler, 1939 (1940), Proc. Acad. Nat. Sei. Phila., XCI, 261, six, 109-220 mm., Contamana, 
Rio Ucayali. 
Anostomus fasciatus Giinther, 1864, Cat. Fish. Brit. Mus., V, 304; 
Cope, 1871 (1872), Proc. Acad. Nat. Sci. Phila., XXIII, 258, Rio Ambyiacu, Hauxwell 
collection; 
Steindachner, 1882 (1883), Denksch. KK. Akad. Wiss. Wien, XLVI, 12, Rio Huallaga, six, 
125-230 mm.; 
Eigenmann and Eigenmann, 1891, Proc. U.S. Nat. Mus., XIV, 50. 
Venezuela and the Amazons to the Rio Paraguay 
The vernacular name Huito-challua is assigned to this species by Steindachner; 
nulilla is Fowler’s name for it. The recurrence of the suffix challhua (fish) in so 
many of Steindachner’s names indicates the possibility that many of them may 
have been named by one person, possibly at one sitting. I did not find such usage 
common in the lowland country, although more prevalent in the mountain sections. 
Genus 167: RHYTIODUS Kner 
Rhytiodus Kner, 1859, Denksch. KKK. Akad. Wiss. Wien, XVIT, 165; 
Higenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 425. 
Garmanina Fowler, 1906 (1907), Proc. Acad. Nat. Sei., Phila., LVIIT, 326, argenteofuscus 
Type: Rhytiodus microlepis Kner 
Upper Amazon, Peru to Rio Negro 
Mouth small, terminal; teeth laminate; premaxillary convex before; maxillary 
teeth flexuose, bicuspid; head slightly depressed, body elongate, subterete; anal 
short; near Schizodon, separated by form of teeth, elongation of body, and broad 
depressed head. 
412. RHyTIODUS MICROLEPIS Kner 
Rhytiodus microlepis Kner, 1859, Denksch. KIx. Akad. Wiss. Wien, XVII, 165, pl. 1, fig. 15, Rio 
Negro; 
Fowler, 1906 (1907), Proc. Acad. Nat. Sci. Phila., LVIII, 326, Pebas; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 425; 
Fowler, 1939 (1940), Proc. Acad. Nat. Sei. Phila., XCI, 261. 
Rio Negro and Peruvian Amazon 
Within our area represented by three specimens in the Philadelphia Academy 
Museum, from Contamana, 153-212 mm. in length. 
413. Ruyriopus ARGENTEOFUSCUS Kner 
Rhytiodus argenteofuscus Kner, 1859, Denksch. KIX. Akad. Wiss. Wien, XVIT, 166, Rio Negro; 
Fowler, 1906 (1907), Proc. Acad. Nat. Sci. Phila., LVIIT, 326; 
EKigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 425. 
Schizodon sagittarius Cope, 1878, Proe. Amer. Phil. Soc., XVII, 689, Peruvian Amazon, Orton 
collection. 
Maranon and Rio Negro 
