242 PROCEEDINGS OF THE ACADEMY OF [Apr., 



below 1. 1.; 12 or 13 predorsal scales; snout 2f to 2| in head; eye 

 3f to 4i; maxillary 4^ to 5; interorbital 2| to 2^; length 105 to 149 

 mm. Only comparatively slight individual variation is noticed in 

 these examples. One example also has an additional lesser external 

 mandibular tooth on the right side, only very inconspicuous. 



(j£-T/7.wrr;?j prisoner, with reference to the dark cross-bands sug- 

 gestive of convict garb.) 



Schizodon fasciatus Agassiz. 



One example 170 mm. 



TETRAGONOPTERIN^ . 

 Tetragonopterus argenteus Cuvier. 



One example 78 mm. 

 Tetragonopterus chalceus Agassiz. 



Two examples, one 80 mm. and the other 97 mm. 

 Astyanax rupununi sp. nov. Fig. 6. 



Head 4; depth 2|; D. iii, 8, i; A. in, 28, i; P. i, 12; V. i, 7; 

 scales 35 in lateral line to caudal base and 3 more on latter; 8 scales 

 above 1. 1.; 6 scales below 1. 1. to ventral origin; 7 scales below 1. 1. 

 to anal origin; 13 predorsal scales; head width ly% in its length; 

 head depth 1; first branched dorsal ray 1; first branched anal ray 

 If; least depth of caudal peduncle 2|; pectoral 1|; ventral 1|; 

 snout 4 in head measured from upper jaw tip; eye 2f ; maxillary 

 21; interorbital 2|. 



Body elongately ovoid, well compressed, deepest at dorsal origin, 

 and edges all rounded convexly except median predorsal ridge, which 

 slightly trenchant. Caudal peduncle compressed, length about 

 equals least depth. 



Head small, compressed, lower profile little more inclined than 

 upper, and flattened sides not converging above or below. Snout 

 convex, length about f its width. Eye rounded, placed about first 

 I in head. Mouth very slightly inclined, transverse, broad, terminal. 

 Maxillary inclined vertically, free, extends back to front eye edge 

 and greatest expansion 3j in eye. Lips firm, rather thin. Upper 

 jaw teeth biserial, outer series smaller and tricuspid, and inner 

 series of larger mostly quineuspid, in all cases median cusp much 

 largest. Mandibular teeth quineuspid, large, powerful and uniserial. 

 At least one of teeth extending from inner upper series on inner base 

 of maxillary, though tooth quite small and obsolete. Mandible 

 very slightly protrudes, strong, and rami scarcely elevated inside 

 mouth. Tongue depressed, rounded, and free in front, rather 



