184 CYPBINIDJE. 



2. DISCOGNATHUS JOHNSTONII. 



(Plate XXXII. fig. 2.) 



Boulenger, Proc. Zool. Soc. 1901, ii. p. 159. 



Body feebly compressed, its depth equal to the length of the head and contained 

 five times in the total length. Head moderately depressed, once and one-third as long 

 as broad, with rounded, feebly projecting snout and nearly flat interorbital region ; 

 eye superolateral, in the second half of the head, its diameter four and two-thirds 

 times in the length of the head, twice and one-fourth in the interorbital width ; width of 

 the mouth half the length of the head; upper lip feebly developed, not fringed; lower 

 lip embracing a mental disk, which is much broader than long ; two minute barbels on 

 each side, not measuring half the diameter of the eye. Dorsal fin with 10 rays, 7 of 

 which are branched, equally distant from the nostrils and from the root of the caudal ; 

 first branched ray longest, two-thirds the length of the head. Anal fin with II 5 rays, 

 first branched ray longest, three-fifths the length of the head. Pectoral fin four-fifths 

 the length of the head, widely separated from the ventral, which is situated below the 

 posterior half of the dorsal. Caudal fin deeply emarginate. Caudal peduncle once and 



5- 



one-third as long as deep. Scales 38^4 between the lateral line and the root of the 

 ventral, 16 round the caudal peduncle. 



Upper parts and fins blackish olive ; labial, gular, and pectoral regions yellowush white, 

 belly brown ; two round deep black spots on the dorsal fin, in the middle of its base. 



The single specimen on which this species is established is 110 millimetres long; 

 the following are its principal measurements. No traces of tubercles are to be seen on 

 the head. 



Measurements (in millimetres). 



Total length (without caudal) 100 



Greatest depth of body 20 



Length of head 21 



Width of head 16 



Length of snout 10 



Diameter of eye 4J 



Interorbital width 10 



Width of mouth 10| 



Longest ray of dorsal 14 



„ „ anal 12 



Length of pectoral 16 



We are indebted to the untiring zeal of Sir Harry Johnston for the discovery of this 

 fish in Lake Victoria ; the single specimen was collected by the late Mr. Doggett. 



