BY J. DOUGLAS OGILBY. 



69 



J{. liypselosoma. 



Pectoral fin as long as the 

 head, and reaching well beyond 

 the origin of the dorsal. 



Caudal fin 3i to 4i in the 

 total length 



Least depth of the peduncle 

 equal to the free space between 

 the anal and caudal fins. 



Dorsal fin unicolorate. 



K. castehiaui. 



Pectoral fins much shorter 

 than the head, and reaching to 

 or nearly to the origin of the 

 dorsal. 



Caudal fin 2i to 31 in the 

 total length. 



Least depth of the peduncle 

 twice the space between the 

 anal and caudal fins 



Dorsal fin tipped with black. 



In Dr. Gilnther's description of hypsehsoma the following 

 passage occurs : — " Ventral fin inserted below the posterior half 

 of the dorsal fin." This is quite incorrect both as regards the 

 species under consideration and the figure of hypselosoma in the 

 Atlas Ichthyologique, in which the ventral fins are directly 

 under the middle of the dorsal, while Bleeker's description of 

 ~ their position is ^^ media tertia parte ventralihus opposita." 



The great variation in the depth of the body in specimens 

 taken from the same slioal is liable to make one look with 

 suspicion upon the value of this character, so much insisted on 

 by Dr. Bleeker. One fact is, however, worthy of notice, namely, 

 that no matter what the depth of the body may be the length of 

 the caudal fin is invariably equal to it, so that the more slender 

 the body is the shorter is the caudal fin, and vice versa; in all other 

 respects the two forms are absolutely identical. 



At the October meeting of this Society I undertook to define 

 at an early date the two recent genera of Rough-backed Herrings, 

 and I embrace this opportunity of redeeming my promise. 



HYPEPtLOPHIN^. 



Anterior dorsal and abdominal profiles more or less compressed 

 and armed with bony serras; supplemental bone of the maxillary 



