14 Annals of the Carnegie Museum. 



Cotypes, 25 specimens, 46-82 mm. Holmia, Potaro River. (C. 

 M. Cat. No. 1005, a-e\ I. U. Cat. No. 11 711.) 



Cotypes, 12 specimens, 28-68 mm. Two hours below Holmia. 

 (C. M. Cat. No. 1006, a-c; I. U. Cat. No. 11 712.) 



Cotypes, 69 specimens, 23-80 mm. Savannah Landing above 

 Kaieteur. (C. M. Cat. No. 1007, a-j \ I. U. Cat. No. 11713.) 



Cotype, 1 specimen, 31 mm. Creek below Savannah Landing 

 above Kaieteur. (C. M. Cat. No. 1008.) 



Cotypes, 9 specimens, 30-62 mm. Tukeit below Kaieteur. (C. 

 M. Cat. No. 1009, a-b; I. U. Cat. No. 11714.) 



Cotypes, 2 specimens, 48-50 mm. Amatuk, Lower Potaro. (C. 

 M. Cat. No. 1010; I. U. Cat. No. 1 1715.) 



Cotype, 1 specimen, 65 mm. Tumatumari, Lower Potaro. (C. 

 M. Cat. No. ion.) 



Very similar to oligolepis, but without trace of caudal spot and with 

 the anal falcate. 



Head 3. 75-4; depth 2.3-2.6 ; D. 1 1 ; A. 23 or 24; scales 5-30 to 

 34-3; eye 2.4-2.5; interorbital 2.8-3. 



Compressed, elevate ; the dorsal profile high, angulated at the 

 origin of the dorsal ; profile depressed over the eye ; ventral profile 

 regularly arched from the snout to the end of the anal. Predorsal area 

 narrowly rounded, with a median series of eight to ten scales ; pre- 

 ventral area bluntly keeled, with a median series of scales ; postventral 

 area narrowly rounded, with a series of saddle-shaped median scales. 



Occipital process 4 in the distance from its base to the dorsal, 

 bordered by three scales on the side ; head narrow, interorbital convex, 

 smooth ; fontanels of equal width, the posterior considerably longer, 

 continued as a groove to the tip of the process. Second suborbital 

 striate, leaving a considerable naked area (entirely covering the cheeks 

 in oligolepis'). Maxillary 2.6 in the head. Usually five teeth in the 

 front row of the premaxillary, the third tooth withdrawn from the line 

 of the rest ; five graduated teeth in the inner series ; the mandible with 

 four large graduate teeth in the front and small ones on the sides. 

 Three small teeth in the maxillary. 



Scales regularly and deeply imbricate, without interpolated rows, 

 each scale with numerous radiating strise ; lateral line sagging to below 

 the middle of the dorsal ; anal sheath of a single series of scales along 

 the first twelve rays ; caudal lobes scaled for half their length. 



Origin of dorsal in advance of the middle of the body, its longest 



