428 ON FISHES FEOM THE RIO JURUA. 



This fish is very rare in the Jurua River, and but a single specimen could be procured 



by Dr. Bach. 



It is a most remarkable form, differing very considerably from any of the species 



with which we are acquainted. 



48. Rhamphiciithys blochii Kaup. 



49. SxEATOGENrS ELEGANS Stdr. 



The presence of a filament of adipose tissue, similar to the dorsal fin of Sternarchus, 

 in a groove along each side of the mental region, to which attention has been drawn by 

 Steindachner in describing his Bhamphichthys elegans, warrants, in my opinion, the 

 establishment of a new genus, for which I propose the name Steatogenys. 



50. Sternopygus virescens Val. 



TETRODONTIDiE. 



51. Tetrodon psittacus B1. Schn. 



EXPLANATION OF THE PLATES. 

 PLATE XXXIX. 



Platystoma juruense, p. 421, with upper and lower views of head 

 and outline of praemaxillary and palatal teeth. 



PLATE XL. 



Fig. 1. Oxydoras trimaculatm, p. 422. 

 Fig. 2. Oxydoras trachyparia, p. 423. 

 Fig. 3. Oxydoras bachi, p. 423. 

 Fig. 4. Oxydoras elongatus, p. 424. 



PLATE XLI. 

 Fig. 1. Ckcetostomus bachi, p. 425. 

 Fig. 2. Acestra gladius, p. 425. 

 Fig. 3. Cetengraulis juruensis, p. 427. 



PLATE XLII. 

 Sternarchus tamandua, p. 427, with upper view of head. 



