208 MEMOIRS OF THE CARNEGIE MUSEUM 



Fourteen specimens, 40-82 mm. Potaro Highland. (C. M. Cat. No. 1706a-c; 

 I. U. Cat. No. 12088.) 



Fourteen specimens, 32-80 mm. Creek at Tukcit Landing. (C. M. Cat. No. 

 I707a-c; I. U. Cat. No. 12089.) 



This species is preeminently a species of the Guiana Plateau. The only ]:)lace 

 in the lowlands (with one doubtful exception) where it was secured is Tukeit, a short 

 distance below the Kaieteur. Giinther records this or a related species from the 

 Essequibo. One specimen whose label was lost may have come from Kumaka. 



Head 5.75-6.25; depth 4.25; D. 5 or 6; A. 37-40; V. 6. Eye 3 in snout, 8 in 

 head, 4 in the distance between the eyes. 



Head short, rounded, its width about equal to its length, its depth about equal 

 to its length without the snout, covered with thick skin above. Maxillary barbel 

 fitting into a groove below the eye, extending to or a little beyond the middle of the 

 pectoral ; mental and post-mental barbels close together, the mental barbel opposite 

 the maxillary barbel, reaching to the tip of the pectoral; the post-mental a little 

 shorter. Gill-membranes broad, overlapping, covered in front by a recurved fold 

 of skin. Dorsal small, rounded, equidistant from caudal and occiput or a little 

 nearer the latter; adipose fin very small, its distance from the dorsal equal to the 

 length of the head; caudal broad, slightly forked, lower lobe the longer, about 3.5-4 

 in the length; distance from snout to anal about 1.25 in the length of the anal; anal 

 margin rounded behind, the rest of its margin straight or but slightly rounded; 

 ventrals reaching anal; pectorals to the ventrals. 



Reddish brown, variously marbled; base of caudal dark, the fin then abruptly 

 lighter; fins, especially the dorsal, ventrals and pectorals hyaline-margined. 



Family V. HYPOPHTHALMID^. 



< Siluridoe anomalopteroe GtJNTHER, Catalogue, V, 1864, 3. 



= Hypophthalmidce Cope, Proc. Am. Assoc. Adv. Sci., XX, 1871, 331. 



Dorsal over the anal, anal very long, its origin near the origin of the second 

 third of the body. Eye placed low, the optic nerve ascending beneath the skin ; a 

 minute air-bladder on either side of the coalesced vertebrte, enclosed by their lateral 

 processes, the scapula, and the process connecting the scapula with the basi-occipital. 



Hypophthalmus Spix. 



Hypophthalmus Spix, Selecta Gen. et Spec. Pise. Bras., 1829, 16, pi. 9 (sp.). — 

 Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 109 (edentatus). 



Notophthalmus Hyrtl, Denkschr. Akad. Wiss. Wien, XVI, 1859, 17 {marginatus = 

 edentatus). 



