Ce ee ee 
1894.] Zoology. 709 
ventral fins. Inhabitants of the fresh waters in the Austrogean (Aus- 
tralasian) realm. 
The genera may be differentiated as follows: 
MErANoTXNIA. Melanoteniines with a little compressed fusiform 
body, slightly curved dorso-rostral contour, and a blackish lateral 
band. 
RuowBATRACTUS. Melanoteniines with a much compressed rhombo- 
fusiform ventradiform body, emarginate dorso-rostral contour, and no 
distinct lateral band. 
Aristeus having been used in 1840 by Duvernoy for a genus of 
Crustaceans, is unavailable for the group so-called by Castelnau, and 
Rhombatractus is used as a substitute. 
Rhombatractus has a curious superficial resemblance to a toxotid on 
account of its compressed body, declining back and ventradiform con- 
tour, but the head is that of an atherinid. 
It may be that the Melanotzniines should be accorded family rank, 
but further data are desirable before such a claim is recognized. One 
of the subordinal characters of the Percesoces, in any case, must be 
modified to fit these fishes.—THEODORE GILL. 
