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Indiana University Studies 



Dorsal hyaline at base, dusky above the hyaline; a dark stripe from 

 the snout to the caudal, widest and most diffuse on head, narrow and 

 sharp on sides. 



Resembling Pimelodella metae which has the upper caudal lobe much 

 longer, the barbel shorter. 



Rhamdia quelen Quoy and Gaimard 



"Vagre" 



15090. I. 167 and 198 mm. Rio Castaiio. Alaracay, July 27. 



15092. I. 195 mm. Maracay Rio Bue, July 30. 



15093, I. 27S mm. El Concejo. Rio Tiquirito, August 2. 



Maxillary barbel to origin of adipose in the largest. 15093. I. to the last 

 fifth of the adipose in 15092, a little beyond its origin in 15090. 



Distance between dorsal and adipose 4 to 5 in the head; adipose 2.6 to 

 2.66 in the length. 



Pectoral spine equals snout and eye. 



Rhamdia guairensis sp. nov. 

 "Vagre" 



Pimelodus humilis Gunther, Cat. Fishes, v. 1864, p. 129 

 Venezuela 



15091. I. Type. 132 mm. paratypes 5, 68 to 220 mm. Rio Guaire near 

 Caracas, August 4. 



Gunther says of his Pimelodus humilis. "pectoral spine slightly ser- 

 rated along both edges". In the specimens before me the pectoral spine 

 is nearly smooth behind and has hooks along the anterior margin, the 

 first one near its tip longer than the spine at its point of attachment. 

 The hooks decreasing in size toward the base. There are other small 

 differences but if it were not for the difference in the pectoral spine I 

 should consider them as belonging to humilis. 



Head 4 to 4.66: depth 6; D. 1.6; A. 11 to 13; distance between dorsal 

 and adipose 1.33 to 1.66 in the head, y 2 to % the length of the adipose ; 

 maxillary reaching to near tip of the ventral or not quite to its base ; 

 outer mental barbels to middle of pectorals ; eye 2.5 in snout. 6 in head. 

 2.33 in interorbital; intermaxillary band of teeth slightly wider at the 

 sides, with incipient backward projecting angle. 



First dorsal ray about equal to snout and eye; caudal deeply forked; 

 the lobes of about equal length, the lower a little the wider; anus a little 

 nearer the eye than to the caudal; pectoral spine but little more than half 

 the length of the fin. about equal to the snout in the young, .66 to .75 of the 

 snout in the adult : anterior margin with about 9 hooks, very strong at the 

 tip. gradually fading out to the base. 



Dorsal with a narrow hyaline area above its base, beyond this the 

 membranes are dark in their posterior half, light in the anterior, the dark 

 becoming diffuse over the entire membrane toward the tip. 



