186 MEMOIRS OF THE CARNEGIE MUSEUM 



Doras costatus Lacepede, Hist. Nat. Poiss., V, 1803, 116, part (South Amer- 

 ica). — Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 268 (Guiana). — 

 Castelnau, Anim. Am. Sud, Poiss., 1855, 48 (Amazon). — Gunther, Cata- 

 logue, V, 1864, 201 (British Guiana; River Cupai). — Eigenmann and Eigen- 

 mann, Proc. Cal. Acad. Sci., (2), I, 1888, 161 (Rio Preto; Rio Puty; San Gon- 

 callo;Xingu Cascade ; Obidos ; Gurupa;Teffe) ; Occasional Papers Cal. Acad. Sci., 

 I, 1890, 231.— Perugia, Ann. Mus. Genova. (2), 1891, 34 (Villa Maria, Para- 

 guay). — Kindle, Ann. N. Y. Acad. Sci., VIII, 1895, 251 (Trocera on the Tocan- 

 tins). — Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903,500 (Para- 

 guay). — Eigenmann, Ann. Carnegie Mus., XXXI, 1907, 116 (Corumba; Laguna 

 Ipacarai); Repts. Princeton Univ. Exp. Patagonia, III, 1910, 393. 

 Pluh/doras costatus Bleeker, Nederl. Tijdschr. Dierk., 1,1863, 16 (name only); 



" Silures de Suriname," 1864, 38 (Surinam). 

 Doras cataphractus (not of Linnaeus) Schomburgk, Fishes Brit. Guiana, I, 1841, 



158 (Rio Negro). 

 Doras arniatulus Muller and Troschel, in Schomburgk, Reisen, III, 1848, 629 

 (Rupununi; Awaricura). 



Two specimens, 105 and 108 mm. Twoca Pan. (C. M. Cat. No. 1638; I. U. 

 Cat. No. 12030.) 



Four specimens, 75-90 mm. Gluck Island. (C. M. Cat. No. 1639; I. U. Cat. 

 No. 12031.) 



One specimen in the Berlin Museum from Guiana and two from Calabozo. 

 Head 3.75; depth 4.25; D. 1,6; A. 11; lateral plates 2 + 30 or 31. Eye 

 1.66-2 in snout, 4-5 in head; 1.5-2 in interorbital. Ventral surfaces of coracoid 

 not exposed. Width at tip of humeral processes greater than the depth; nuchal 

 region bluntly roof-shaped. Head granular to in front of posterior nares; nasal 

 bone with blunt serration, scarcely raised; orbit with granular margin; maxillary 

 barbel reaching to tip of humeral process, outer mental to base of pectoral. 18 Upper 

 jaw longer; width of mouth less than half the distance between the gill-openings. 

 Pectoral spine striate above and below, strongly serrate in front and behind, reach- 

 ing beyond base of ventrals; dorsal spine shorter than pectoral spine, its sides 

 striate, serrate on its anterior and posterior margin, the serrae on the posterior 

 margin much smaller; teeth on front margin of dorsal spine antrorse; largest near 

 the tip; humeral process reaching to fourth fifth of the pectoral spine; caudal 

 forked; height of highest lateral plate about half the length of the head, each plate 

 with numerous small backward-directed spines, in several vertical rows in front, 



a To its middle in the larger specimen at Berlin. 



