ANNOTATED LIST OF THE SPECIES 109 
Steindachner, 1882 (1883), Denksch. KIx. Akad. Wiss. Wien, XLVI, 4, one specimen, 320 
mm., Rio Huallaga; 
Pseudoplatystoma fasciatum Bleeker, 1863, Nederl. Tijdsch. Dierk., I, 97; 
Eigenmann and EHigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 208; 
Higenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 391; 
Eigenmann, 1912, Mem. Carnegie Mus., V, 182; 
Fowler, 1939 (1940), Proc. Acad. Nat. Sei. Phila., XCI, 224, Contamana. 
Platystoma punctifer Castelnau, 1855, Anim. Amér. Sud, Poiss., 40, pl. xix, fig. 2, Amazon. 
La Plata northward to the Magdalena, Orinoco, and Guiana 
15763, 2, about 270 and 296 mm., Manaos, Allen, December, 1920. 
15764, 1, 163 mm., Lago Cashiboya, Allen, August, 1920. 
, 1, 450 mm., Amazon, Iquitos, Allen, 1920. 
Head 3.16; eye small, 14 in head, exactly centered from front to back, 3.3 in 
flat interorbital space; latter 4.8 in length of head; fontanel long, sharply pointed 
forward, deep in the middle, less sharp posteriorly, not reaching occipital process; 
mouth wide, equals isthmus of snout just before the eye, 3.16 in length of head. 
Occipital process an elongate triangle, its divided tip nearly in contact with the 
sharply acute anterior angle of the dorsal plate, whose posterior margin forms an 
are, the entire plate being arrow-shaped. Branchiostegals not entering upper leg 
of membrane or lateral aspect of head, leaving that portion of opercle a loose flap, 
but rays prominent below. Barbels three pairs, the narials extending nearly to 
end of head; the inner pair of mental barbels reach beyond the level of the eye, the 
posterior pair, inserted posterior and lateral to the preceding, thick, wiry, flattened 
on one side, taper to a fine filament reaching to the middle of the pectoral fins. 
Nares with the anterior pair at the edge of the snout guarded by a white flap directed 
forward; the posterior pair separated by a space one fourth the length of the snout 
from the preceding, and more than half the interorbital space apart, guarded by 
similar flaps turned backward. 
Prominent patches of sensory canals appear as the skin dries; a narrow band of 
canals follows the lateral line from the base of the caudal fin forward; beneath the 
dorsal fin this band widens out so as to form a cornucopia with its mouth at the 
opercular aperture, where its width is equal to that of the interorbital space; a good- 
sized patch of canals occurs in the inter- and post-narial region, another forms a 
narrow area on the preorbital region; a fan-shaped suborbital is confluent with a 
post-orbital; two large patches occupy the forward border of the opercle. Many 
of the canals anastomose into a network, and terminate in minute white pustules. 
The produced premaxillary exposes many of its minute teeth beyond the border of 
the mandible. 
Snout much flattened, its depth contained four times in its width at the level 
of the posterior nares; greatest width of head contained 2.23 in its length; posterior 
part of the head trapezoidal in section, becoming a rounded equilateral triangle 
before the dorsal fin, body tapering with but slight compression to the caudal, the 
latter part of the trunk being oval throughout. 
Ventral, anal, and caudal fins thickened and fleshy; D. I, 6; its spine slender, 
pointed, long, its fine retrorse hooks limited to a few at the tip, mostly enclosed in 
