438 OPHIOCEPHALID^:. 



1. OPHIOCEPHALUS OBSCURUS. 

 (Plate LXXXII.) 



Giinther, Cat. Fish. iii. p. 476 (1861), and Petherick's Trav. ii. p. 215, pi. ii. %. B (1869) ; Stein- 

 dachner, Sitzb. Ak. Wien, lxxxiii. i. 1881, p. 197, and Notes Leyd. Mus. xvi. 1894, p. 36; 

 Boulenger, Poiss. Bass. Congo, p. 368 (1901). 



Depth of body five to six and a half times in the total length, length of head three 

 to three and a half times. Head once and three-fifths to twice as long as broad ; 

 lower jaw projecting beyond the upper; snout rounded, once (young) to twice as long 

 as the diameter of the eye, which is five (young) to nine times in the length of the 

 head and once and a half to twice and one-fifth in the interorbital width ; eye supero- 

 lateral ; maxillary extending beyond the vertical of the posterior border of the eye ; a 

 few large canine teeth on each side of the lower jaw; nasal tentacle three-fifths to 

 two-thirds the diameter of the eye; 10 to 12 series of scales between the eye and the 

 angle of the praeoperculum. Gill-rakers short, tubercular, covered with asperities, 

 8 or 9 on lower part of anterior arch. 40 to 45 rays in the dorsal fin, the longest two- 

 fifths to three-fifths the length of the head. Anal fin similar but shorter, with 26 to 

 31 rays. Pectoral fin measuring half to three-fifths the length of the head, longer 

 than the ventral. Caudal fin rounded or subacuminate. Caudal peduncle once and a 

 half to once and two-thirds as deep as long. Scales striated, with smooth or feebly 

 denticulate border, 62 to 76 in a longitudinal series above the lateral line, 44^ in a 



& ' 12-15 



transverse series below the first dorsal ray; 34 to 42 tubules in the lateral line. 



Olive above, greyish beneath, according to a sketch made by Mr. Loat ; a lateral 

 series of large, rounded, oval, or rhombic dark spots edged with black, sometimes with 

 a lighter outer border; irregular blackish spots above and beneath the lateral series; 

 a broad blackish band along each side of the head, from the eye to the edge of the 

 gill-cover ; lower surface of head marbled with whitish ; fins greyish olive, spotted with 

 black. In the very young, a broad blackish lateral band extends from the tip of the 

 snout, through the eye, to the root of the caudal fin, and is followed, on the basal part 

 of the latter, by a small, black, light-edged ocellar spot. 



This fish reaches a length of 350 millimetres. 



Ophiocephalus obscurus, which is very closely related to the 0. litems of Cuvier and 

 Valenciennes, from Borneo, Sumatra, and Siam, was first described by Giinther from 

 two specimens, West Africa, locality unknown ; it has since been found at Gondokoro 

 by Consul Petherick, in the White Nile and the Bahr-el-Seraf, in Lake Chad, and in 

 the rivers of West Afnca, from the Gambia to the Congo. 



