90 THE AMERICAN CHARACIDAE. 



Specimens examined. 



Locality Collector 



Aruataima, Upper Potaro River Eigenmann 



Holmia, Upper Potaro River Eigenmann 



Two hours below Holmia Eigenmann 



Savannah Landing above Kaieteur Eigenmann 



Creek below Savannah Landing Eigenmann 



above Kaieteur 



Tukeit, Lower Potaro River Eigenmann 



Amatuk, Lower Potaro River Eigenmann 



Tumatumari, Lower Potaro River Eigenmann 



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

 the anal falcate. 



Head 3.75-4; depth 2.3-2.6; D. 11; 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; preventral area bluntly keeled, with a 

 median series of scales; postventral area narrowly rounded, with a series of 

 saddle-shaped median scales. 



Occipital process four 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. 

 Maxillary 2.6 in the head. Usually five teeth in the front row of the premaxil- 

 lary, the third tooth withdrawn from the line of the rest; five graduated teeth 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 striae; 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 ray two and 

 a half as long as the penultimate, three and a third in the length; caudal lobes 

 equal, a little longer than the longest dorsal ray; anal emarginate, its longest 



