114 FISHES OF WESTERN SOUTH AMERICA 
tending far beyond the caudal fin of the fish; eye superior; adipose longer than 
anal; upper jaw as in Sorubim much produced, and toothed over its entire ventral 
surface; caudal deeply forked, the lobes pointed and equalling or surpassing half 
the body length. 
57. PLATYSTOMATICHTHYS STURIO (Kner) 
Platystoma sturio IWner, 1857, Sitzb. Kix. Akad. Wiss. Wien, X XVI, 395. 
Platystomatichthys sturio Bleeker, 1863, Nederl. Tijdsch. Dierk., I, 98; 
Higenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 218; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 392. 
Fowler, 1939 (1940), Proc. Acad. Nat. Sci. Phila., XCI, 225, figs. 8-10, one, Contamana. 
The Amazon system 
15654, 1, 280 mm. to end of middle caudal rays, Iquitos, Allen, September, 1920. 
Genus 24: HEMISORUBIM Bleeker 
Platystoma Cuvier and Valenciennes (part), 1840, Hist. Nat. Poiss., XV, 27, preoccupied in Diptera. 
Hemisorubim Bleeker, 1863, Nederl. Tijdsch. Dierk., I, 97, platyrhynchos; 
Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 205; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 391; 
Eigenmann, 1912, Mem. Carnegie Mus., V, 181. 
Type: Platystoma platyrhynchos Cuvier and Valenciennes 
Peruvian Amazon and Séo Paolo northward 
Among the long-headed genera of Pimelodinae, Hemisorubim is distinguished 
for the protraction of the lower jaw beyond the upper, the latter being thin and 
sharply truncate; intermaxillary band of teeth constricted in the center; vomerine 
patch single and much wider than the above, lying close to the large palatine 
patches; width of the mouth at its angle 1.5 in the greatest width of the head; mental 
barbels approximated and near the edge of the lip; occipital process shorter than 
the dorsal plate and reaching it; postorbital region striate and granulate; sides of 
head and snout reticulated. 
58. HEMISORUBIM PLATYRHYNCHOS (Cuvier and Valenciennes) 
Platystoma platyrhynchos Cuvier and Valenciennes, 1840, Hist. Nat. Poiss., XV, 27; 
Castelnau, 1855, Anim. Amér. Sud, Poiss., 40. 
Hemisorubim platyrhynchos Bleeker, 1863, Nederl. Tijdsch. Dierk., I, 97; 
Eigenmann and Eigenmann, 1888, Proc. Cal. Acad. Sci., (2), I, 138; 
Eigenmann and Eigenmann, 1890, Oce. Papers Cal. Acad. Sei., I, 151; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 391; 
Fowler, 1939 (1940), Proc. Acad. Nat. Sci. Phila., XCI, 224, Contamana. 
Hemisorubim platyrhynchus Giinther, 1864, Cat. Fish. Brit. Mus., V, 109; 
Cope, 1878, Proc. Amer. Phil. Soc., XVII, 674, Peruvian Amazon. 
