SOUTH AMERICAN NEMATOGNATHI. 



31 



Sides and back with narrow black lines forming coarse 

 reticulations; a series of large round black spots on the 

 lower part of the side; all the tins spotted with black. Max- 

 illary barbels reaching little beyond base of pectorals, the 

 post-mentals reaching somewhat farther. 



Pseudo pi aty stoma fasciatum nigricans var. nov. 



Types, Nos. 7301 and 7311; two specimens, .40-.60 m. Xingu. 



Black above, gradually shading into light below; lateral 

 bars of the abdominal region extending to the edge of the 

 belly; a series of large black spots along the lower parts of 

 the sides; all the fins conspicuously spotted. Maxillary 

 barbel reaching to origin of dorsal. 



Pseudoplatystoma fasciatum brevefile var. nov. 



Type, No. 7317; one specimen, .62 m. Goyaz, Senhor Honorio 



Vertical bars of abdominal region broken up into spots, 

 those of the caudal region widened at their loAver termina- 

 tion; a series of veiy large lateral spots on lower part of 

 sides. Maxillary barbels reaching to edge of opercle. 



XXY. Tachisurus Lacepede. 

 Tachisurus upsulonophorus sp. nov. 



Type, No. 23750; one specimen, .33 m. Rio Grande do Sul. 



Closely related to T. platypogon (Gunther) from which 

 it may be distinguished by the following characters: 



platypogon. 



Inner margins of palatine patclies 

 of teeth straight; the distance be- 

 tween them equal to the diameter of 

 the pupil. 



Fontanel abruptly continued as a 

 groove. 



Granulations of the head fine, ir- 

 regularly scattered. 



Anterior margin of the dorsal spine 

 with sharp straight teeth. 



upsulonophorus. 



Inner margins of palatine patches 

 of teeth concave, the distance be- 

 tween them greater than the longi- 

 tudinal diameter of the eye. 



Fontanel gradually merging into 

 a groove. 



Granulations of the head coarse, 

 arranged in series. 



Anterior margin of the dorsal spine 

 with granules. 



