1868.] DR. A. GiJNTHEU ON N KW AMERICAN HbHES. 245 



fins ; the fourth corresponding to the vent, the fifth to the middle 

 of the anal, the sixth from the adipose fin, and the seventh round 

 the last caudal scales. Anterior part of the base of the dorsal and 

 the ventrals deep black ; the other fins yellowish. 



Several examples, the largest 6 inches long, were obtained by 

 Mr. Bartlett at Xeberos. All of them have one side of the gill- 

 cavity infested with a parasitic crustacean. 



Tetragonopterus ovalis. 



D. 11. A. 26. L. lat. 31. L. transv. 5|/t). 



The height of the body is one-half of the total length (without 

 caudal) ; the length of the head is contained thrice and two-thirds 

 in it. Upper profile rather more convex than lower, sligiitly concave 

 on the nape. The diameter of the eye is more than the width of the 

 interorbital space, less than the length of the snout, and one-third 

 of that of the head. The maxillary extends somewhat beyond the 

 vertical from the front margin of the orbit. Origin of the dorsal fin 

 immediately behind tlie root of the ventral. Pectorals extending 

 beyond the ventrals, ventrals to the vent. There are four longi- 

 tudinal series of scales between the lateral line and ventral fin. 

 Humeral spot indistinct ; caudal spot diffuse, extending over the 

 base of the fin. Remainder of the body uniformly coloured. 



A single example, 4 inches long, was obtained by Mr. Bartlett 

 at Xeberos. 



Aphyocharax, g. u. 



This genus belongs to the Tetniyonopterina , and is, technically, 

 distinguished from Chirodon by the presence of maxillary teeth. 



Dorsal fin placed in- the middle of the length of the bodv, behind 

 the ventrals ; anal rather long. Body oblong, covered with scales 

 of moderate size. Lateral line visible on a part of the scales only. 

 Abdomen rounded before the ventrals. Cleft of the mouth narrow ; 

 maxillary short ; intermaxillary, maxillary, and mandibles with a 

 single series of pointed teeth, those in the intermaxillary haviug a 

 minute lobe on one or both sides ; all the others appear to be simply 

 pointed. 



Aphyocharax pusillus. 



D. 9. A. 18. V. 8. L. lat. 3(j. L. transv. 12. 



The height of the body equals the length of tlie head, and is two- 

 ninths of the total (without caudal). The diameter of the eye is 

 two-sevenths of the length of the head, more than that of the snout, 

 and less than the width of the interorbital space ; maxillary extend- 

 ing somewhat beyond the vertical from the anterior margin of the 

 orbit. Intermaxillary with about seven, mandible with nine teeth 

 on each side ; maxillary teeth very small, occupying abtmt one-third 

 of the length of the bone. Jaws even in front, the mandible pro- 

 jecting when the mouth is open. Origin of the dorsal fin midwav 

 between the end of the snout and the root of the caudal, behind the 



