440 PROCEEDINGS OF THE ACADEMY OF [Oct., 



fails to indicate either the humeral or the caudal blotch which are 

 here very distinct. 



Dr. Eigenmann has recently recorded under the name Poecilurichthys 

 dbramis some specimens from Paraguay which apparently are the 

 present species. 



Tetragonopterus chalceus Agassiz.^ 



Cope, Proc. Acad. Nat. Sci. Phila., 1871 (1872), p. 260. Ambyiacu River, 

 ^ Equador. John Hauxwell. Cope, I.e., p. 291. Between the mouth 



of the Rio Negro and the Peruvian Amazon or Ucayale River. Robert 



Perkins. Cope, Proc. Amer. Philos. Soc. Phila., XVII, 1877-78 



(May 17, 1878), p. 691. Maranon. Prof. J. Orton. 

 Tetragonopterus ortonii Cope, I.e. XI, 1869-70 (August 16, 1870), p. 566. 



Pebas, Peru. John Hauxwell. 



Head 3 to 3§; depth If to 2; D. in, 9; A. iv, 30, i to iv, 36, i, usually 

 33 developed rays, frequently 34, and other numbers rare or exceptional; 

 29 to 31 scales in lateral line to base of caudal, usually 30, and 3 more on 

 latter ; 8 scales in an oblique series back from origin of dorsal to lateral 

 line; 5 scales from root of ventral to lateral line; 6 scales from origin 

 of anal, not counting any on fin, to lateral line; length of 13 examples 

 from 2y|- to 4|- inches. Hauxwell, Perkins and Orton. 



The example recorded from Pebas, eastern Peru, by Cope as T. 

 ortonii is identical. It shows: Head 2|; depth about ly^^; D. in, 9; 

 A. IV, 33?; scales (squamation damaged) about 28? in lateral line to 

 base of caudal; snout about 4 in head, measured from tip of upper jaw; 

 eye 2^ ; interorbital space 3. A dusky blotch at base of caudal. Length 

 {caudal damaged) 2^^ inches. John Hauxwell. 



Tetragonopterus ortonii Gill is possibly this species, though I have 

 not examined the type. 

 Tetragonopterus ovalis (Gunther). Fig. 38. 



Tetragonopterus chalceus Cope, Proc. Amer. Philos. Soc. Phila., XVII, 

 1877-78 (May 17, 1878), p. 691. Maranon. Prof. J. Orton. 



Interorbital space 2^ in head. Body compressed. Predorsal region 

 with a median keel, postdorsal region rounded, preventral region a little 

 broad and flattened with a lateral keel on each side, and postventral 

 region trenchant. Snout broad and convex. Several small teeth 

 at base of maxillary inside. Some teeth in inner series of upper 

 jaw with more than 5 cusps. Tongue fleshy, thick and little free. 

 Interorbital space broad and convex. Gill-opening forward oppo- 

 site anterior margin of orbit. Rakers 9 + 11, lanceolate, half of 

 filaments, which are f of eye. Each scale with several radiating 

 striae. Tubes in lateral line simple. Vent shortly before anal. 

 Color in alcohol with scales faded brassy-brown, back darker, also 

 top of head. Side of head burnished silvery. Fins pale brownish. 



