182 MEMOIRS OF THE CARNEGIE MUSEUM 



I have been able to examine a specimen collected by Schomburgk and now 

 in the Berlin Museum. 



Head 3; depth 6-7; D. 1,6; A. 10; Br. 11; eye 7 in head, 3 in snout, 1.75 

 in interorbital. 



Head depressed, rounded on occiput; eye directed largely upward. Lower 

 jaw projecting and entering profile. Maxillary barbels extending past dorsal fin; 

 mental barbels approximate, extending to below eyes; post-mentals to pectorals. 

 Teeth in the lower jaw in a narrow band. Vomerine and palatine teeth close 

 behind the premaxillary teeth, the vomerine teeth in a single patch separate from 

 the palatine patches. 



Dorsal spine weak and slender, 2.5 in head, its distance from the snout greater 

 than its distance from the posterior margin of the adipose fin, much nearer base 

 of ventrals than base of pectorals; with retrorse teeth behind. Adipose fin longer 

 than anal. Lower caudal lobe wider and longer than upper, rounded in adult, 

 pointed in young. Ventrals extending two-fifths their length beyond the vent. 

 Pectoral spine 1.6 in head, usually with equally strong teeth in front and behind. 



White below, olivaceous above, with a few jet-black spots scattered on sides, 

 and usually a similar spot at base of upper caudal lobe; fins plain. 



PSEUDOPLATYSTOMA Agassiz. 



Platystoma Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 23 (sp.). 

 Sorubim Spix, Selecta Gen. et Spec. Pise. Bras., 1829, pis. 12-15 (sp.). 

 Pseudoplatystoma Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 (fasciatum). 

 Hemiplaty stoma Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 (tigrinum). 



Type, Silurus fasciatus Linnaeus (in part) . 



Upper jaw little longer than lower; teeth of the jaws alike; vomerine and 



palatine patches of teeth more or less united, the two forming a comma-shaped 



patch on each side of the palate; gill-rakers short, spine-like, not overlapping; 



caudal deeply lobed, the lobes rounded (except in very young), the rays very much 



branched, giving the fin a leathery texture. Branchiostegals 14 or 15; barbels 



short. 



55. Pseudoplatystoma fasciatum (Linnaeus). 



Tiger-fish. 



Silurus fasciatus Linnaeus, Syst. Nat., ed. 12, I, 1766, 505. — Gmelin, Syst. Nat., 

 I, iii, 1788, 1359.— Bonnaterre, Tabl. Enc. Meth., Ichth., 1788, 154, 252- 

 Bloch, Ausl. Fische, VIII, 1794, 30, pi. 366.— Bloch and Schneider, Syst. 

 Ichth., 1801, 382. 



