SOUTH AMERICAN NEMATOGNATHI. 73 



Ventrals lf-2 in head. 



Pectoral spine If in head, its outer margin faintly 

 serrate, its inner margin more strongly serrate. 



Color: violet with reflections of blue and green, shad- 

 ing into bluish-silvery below; sometimes with numerous 

 dots on sides and belly; fins dusky; the dorsal portion 

 of the inner surface of paired fins sometimes black. 



Head 3J-4; depth 5-5 J; D. I, 7; A. 18-19. 



We have examined 9 3 specimens .28-. 31 m. 

 Panama; Acapulco. 



43. Tachisurus upsulonophorus, 



Tachisurus U2)sulonophorus'E. &. E. Proc. Cal. Acad. Sci. 2d Ser. ii, 

 1889, 31; one specimen .33 m. Kio Grande do Sul. 



Form of T. platypogon, the head wider and more de- 

 pressed. Width of the body equal to its depth. Profile 

 slightly arched, not very steep. Head flattish above the 

 eyes, its greatest depth equal to the post orbital portion 

 plus the orbit; greatest width of head 1J in its length. 

 Top of head rather coarsely granulated, the granules 

 arranged in regular longitudinal series. Occipital pro- 

 cess strongly keeled, longer than broad, its granulations 

 also striate. Fontanel gradually passing into a groove 

 which is continued to base of occipital process. 



Eye large, its vertical diameter 1| in its longitudinal 

 diameter which is 2J- in the snout, 6J in the head, 3 in 

 the interocular. 



Maxillary barbels reaching little beyond base of pec- 

 torals, postmentals not quite to pectorals, mentals not 

 to gill-opening. 



Snout somewhat blunt, less decurved 

 than in platypogon; uppre jaw slightly 

 projecting; teeth villiform, the inner 

 margins of the palatine patches con- 

 cave, distant 1| longitudinal diameters of 

 the eye. 



