174 Annals of the Carnegie Museum. 



10. Phenacogaster beni sp. nov. 

 Plate VI, fig. 4. 



Type. — One specimen, 48 mm. C. M. No. 3229. Villa Bella, Rio Beni, Oct. 5 

 1909. 



Cotypes. — Two specimens, 39 to 41 mm. to base of caudal. C. M. No. 3230. 

 Same place and date. 



Cotype. — One specimen, 46 mm. C. M. No. 3230^. Maciel, Rio Guapore, 

 Aug. 3, 1909. 



Head 4.4; depth 2.66; D. 10; A. 36 or 37; scales 8-39-5; e Y e 2 -75; 

 interorbital 3. No, to three, scales in the angles of the overlapping 

 scales of the ventral surface. Premaxillary with three tricuspid, and 

 four or five conical, teeth in the outer series, seven tricuspid and three 

 conical teeth in the inner series. Dentary with five tricuspid and eight 

 conical teeth. A faint humeral spot over the seventh scale of the 

 lateral line; a dark, deep lying line; a small caudal spot, and the 

 middle caudal rays dotted. 



Allied to P. microstictus Eigenmann, not as deep. 



In one of the specimens the humeral spot is absent and the lateral 

 line is developed on but twenty-six scales. 



Vesicatrus gen. nov. 



Phenacogaster with an incomplete lateral line. Type, V. tegatus, 

 the only species. 



II. Vesicatrus tegatus sp. nov. 

 Plate VII, fig. 1. 



Type. — One specimen, 33 mm. to base of caudal. C. M. No. 3201. Jauru, 

 Upper Paraguay basin. June 2, 1909. 



Cotypes. — Seven specimens, 31 to 33 mm. to base of caudal. C. M. No. 3202. 

 Same place and date. 



Cotype. — One specimen, 30 mm. to base of caudal. C. M. No. 3202. Caceres, 

 Upper Paraguay basin. May 24, 1909. 



Head 3.75-4; depth 2.75; D. 10; A. 34-38, usually 36. Scales 6 

 or 7-37 (rarely 35)~4; eye 3 in the head, a little greater than the 

 interorbital. Compressed, subrhomboidal. Ventral profile regularly 

 arched; dorsal profile somewhat depressed over the eye, rising to the 

 dorsal fin. Preventral area fiat, with two series of larger scales over- 

 lapping along the middle, sometimes a scale in the angle between the 

 two scales of a pair; predorsal area obscurely keeled, apparently with 

 a complete median series of scales. Occipital process about 4.5 times 



