332 



DR. A. GtJNTHER ON 



[Nov. 18, 



specimens of this species ; he collected them on the River 

 Dunkwa, and at ISTyankoma, R. Enon. 



Some of these specimens differ in certain points, as the height 

 of the spinous dorsal fin, the form of the cheeks, (fee, from those 

 previously received and among themselves. However, I regard 

 these differences as merely individual variations ; they are 

 indicated in the following table, in which measurements are 

 given in millimetres ; the teeth are counted on one side of the 

 upper jaw only : — 



Chromis discolor, sp. n. 



D. If. A. f. L. lat. 29-30. L. transv. 3/11. 

 Nineteen or twenty teeth on each side of the upper 



jaw. 



Maxillary rather short, not extending to the vertical from the 

 front margin of the eye. Upper profile of the snout straight ; 

 interorbital space flat, wider than the orbit, which is nearly one 

 fourth of the length of the head. Three series of scales on the 



regard the size and number of teeth as a vahiable specific character which should 

 always be taken into consideration, combined with a statement of the size of the 

 specimens to which the statement of the dental number applies. 



Therefore I must demur to Mr. Boulenger's statement that in C. ogotcensis the 

 teeth " vary " from 15 to 30 on each side {I. c. p. 466). The tj'pical specimen, from 

 which alone mj^ original description is taken, is 170 millim. long, and probably 

 mature. The collector put into the same bottle two young specimens, 62 and 

 66 millim. long, which pi-esumablj' maj^ belong to the same species. I say presum- 

 ably, for I confess that the uncertainty and difficulties attending the determination 

 and specific discrimination of the young of closely-allied species of Chromis are too 

 great to allow me to offer a categorical opinion upon them. 



