eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 475 



Key to the Guiana Species of Pachypops. 



a. Soft dorsal rays 25-27; second anal spine enlarged, 1.2-1.5 in the longest anal rays. Sides and back without 



large dark spots furcraeus. 



aa. Soft dorsal rays 30-32; the one anal spine scarcely heavier than the dorsal spines, 3.1 in the head. Sides 

 and back with dark spots grunniens. 



321. Pachypops furcraeus (Lacepede). 

 Perca furcrcea Lacepede, Hist. Nat. Poiss., IV, 1802, 398, 424 (Surinam). 

 Corvina furcrcea Cuvier and Valenciennes, Hist. Nat. Poiss., V, 1830, 111 (same 



type). 

 Pachypops furcraeus Steindachner, "Scisenoiden Brasiliens," etc., in SB. Akad. Wiss. 



Wien, XLI, 1863, 7, pi. 1 (Rio Negro). — Jordan and Eigenmann, Rept. U. S. 



Fish Com. for 1886, 1889, 413 (Rio Negro).— Eigenmann, Proc. U. S. Nat. 



Mus., XIV, 1891, 67 (Amazons; name only); Repts. Princeton Univ. Exp. 



Patagonia, III, 1910, 468.— Berg, An. Mus. Nac. Buenos Aires, IV, 1895, 53 



(Montevideo). — Jordan and Evermann, Rept. U. S. Fish Com. for 1895, 



1896, 399 (name only); Bull. U. S. Nat. Mus. No. 47, II, 1898, 1459 (same 



specimens as Jordan and Eigenmann). — Eigenmann, Repts. Princeton Univ. 



Exp. Patagonia, III, 1910, 468. 

 Pachyurus furcrceus Steindachner, " Ichthyologische Beitrage," viii, 1879, 12 



(Surinam; Rio Trombetas; Amazon, near Cameta). 

 Corvina biloba Cuvier and Valenciennes, Hist. Nat. Poiss., V, 1830, 112 (habitat 



not known). 

 Pachypops biloba Steindachner, "Ichthyologische Notizen," i, 1864, 7 (Surinam). 



One specimen, 193 mm. Creek in Mora Passage. (C. M. Cat. No. 2474.) 



Three specimens, 56, 76, and 132 mm. Wismar. (C. M. Cat. No. 2475a; 

 I. U. Cat. No. 12570.) 



Nine hundred eighteen specimens, 31-121 mm. Bartica sand-bank. (C. M. 

 Cat. No. 2476a-z; I. U. Cat. No. 12571.) 



Head 2.9-3.4; depth 3.5-3.8; D. X-I,25-27; A. 11,6; about fifty-eight pores 

 in the lateral line, fifty-two oblique series above the lateral line, eleven scales in an 

 almost vertical series between the front of the soft dorsal and the lateral line; 

 width of eye 1.25 in its length, length of eye 2.9-3.1 in the head. Interorbital 1.5 

 in the eye. 



Compressed; elongate; dorsal profile convex; interorbital flatfish ; snout blunt, 

 scarcely equal to the eye. Bones of the head very cavernous and translucent; 

 preorbital turgid, overhanging the very small inferior mouth. Maxillary entirely 

 concealed when the mouth is closed, just reaching the anterior margin of the pupil. 



