180 MEMOIRS OF THE CARNEGIE MUSEUM 



Piratinga Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 100 (reticulata). 

 Malacobagrus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 100 (filamentosus). 



Type, Platystoma vaillanti Cuvier and Valenciennes. 



Vomer and palate with villiform teeth; inner teeth of the jaws slender and 

 freely movable; caudal forked; head covered with skin; occipital process short, 

 concealed, not reaching the dorsal in the adult. 



53. Brachyplatystoma vaillanti (Cuvier and Valenciennes). (Plate XVII, fig. 3.) 



"Laulau." 



Platystoma vaillanti Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 21, pi. 

 423 (Cayenne and Surinam) .— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 397 

 (Para). — Gunther, Catalogue. V, 1864, 108 (Demerara). — Peters, MB. Akad. 

 Wiss. Berlin, 1877, 469 (Calabozo). 

 Brachyplatystoma vaillanti Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 (name 

 only) ; ' ' Silures de Suriname, ' ' 1 864, 70 (Surinam) . — Eigenm ann and Eigenmann, 

 Proc. Cal. Acad. Sci., (2), 1, 1888, 136 (Tabatinga; Para; Porto do Moz; Arary; 

 Rio Puty; Juiz de Fora); Occasional Papers Cal. Acad. Sci., I, 1890, 196. — 

 Eigenmann and Bean, Proc. U. S. Nat. Mus., XXXI, 1907, 662 (Amazon).— 

 Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 390. 

 Platystoma affine Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 24 

 (Brazil). — Castelnau, Anim. Am. Sud, Poiss., 1855, 40 (Araguay).— 

 Gunther, Catalogue, V, 1864, 109 (copied). 

 I have examined the specimen mentioned by Bleeker and: 

 One specimen, head only. Rockstone. (C. M. Cat. No. 1288.) 

 Sixteen specimens, 178-290 mm. to tip of middle caudal rays. Georgetown 

 market. (C. M. Cat. No. 170a-d; I. U. Cat, No. 12083.) 



Head 3.4-3.5; depth 5.5; D. 1,6; A. 13; eye 4 in snout; 10 in head, 2.5 in 

 interorbital in a specimen 280 mm. long to tip of middle caudal rays, 4 in snout, 

 9 in head, and 2.5 in interorbital in a specimen 178 mm. long to tip of middle 

 caudal rays; adipose fin 4.4-4.5 in the length. 



Subtriangular in section at the dorsal fin, the snout much depressed, the tail 

 moderately compressed; occipital crest narrow, not much tapering, its width near 

 the middle one-fourth its length in the Georgetown specimens, reaching but not join- 

 ing the dorsal plate. An elongate depression along middle of the head ; fontanel nar- 

 row, extending to the posterior margin of the eye; mouth lunate from below, the 

 upper jaw scarcely projecting ; maxillary barbel extending beyond tip of middle 

 caudal rays in all the Georgetown specimens; mental barbels opposite angle of 



