104 CHAKACINID^E. 



species at Akhmim, but at Girga the word "kelp" was placed in front, "kelp 

 molulier" ; " Mbum'bo" (>UJ1 <^K), "Marneadar" (scU^-), "neVko" (/U), all in 

 use between Shellal and Wady Haifa; iC shanko " (/i-) at Kosheh ; " shan" (J&) at 

 Arko; " kass" (^jj) at Korti, and by some men at Arko, also at Omdurman, Blue 

 Nile. 



2. HYDROCYON LINEATUS. 

 (Plate XVII. fig. 2.) 



? Hydrocynus vittatus, Castelnau, Mem. Poiss. Afr. Austr. p. 65 (1861). 



Hydrocyon lineatus, Bleeker, Nat. Verh. Yer. Haarlem, xviii. 1862, no. 2, p. 125 ; Griinther, Cat. 



Fish. v. p. 352 (1864) ; Boulenger, Poiss. Bass. Congo, p. 143 (1901). 

 Hydrocyon forskalii, part., Peters, Reise Mossamb. iv. p. 69 (1868). 

 Hydrocyon forskalii (non Cuv.), Steindaclmer, Notes Leyd. Mus. xvi. 1894, p. 62. 



As already mentioned in 1901, when dealing with the fauna of the Congo Basin, it 

 is with considerable diffidence that I retain this form as a species distinct from 

 H forskalii, with which it agrees in most characters. The differences on which 

 H. lineatus has been established reside in the shorter body, with fewer scales in the 

 lateral line, the series of dark spots or longitudinal dark streaks on the series of scales 

 below the lateral line, and the presence of a deep black spot on the adipose dorsal fin. 

 Although these characters, occurring in combination, appear to me to warrant, at least 

 provisionally, the recognition of the species lineatus, it is nevertheless true that each 

 of them taken separately varies in this form and in H. forskalii to such an extent as 

 to produce an overlap conducive of hesitation in the determination of certain specimens. 

 These intermediate specimens, referred to E. forskalii, are from the White Nile, the 

 Senegal, and the Niger, whilst the extreme specimens of the type species are from the 

 Nile proper, and all the specimens from south of the Equator hitherto examined fall 

 into the definition of H. lineatus, which might be regarded merely as a southern form 

 of Cuvier's species. 



In the specimens referred by me to II. lineatus, and of which a list is given below, 

 the depth of the body is contained three and one-fourth to four and a half times in 

 the total length, the length of the head three and a half to four and one-fourth 

 times ; the branched rays in the anal fin number 10 to 13, the scales in the lateral line 

 44 to 48. The caudal peduncle is only once and one-thircl to once and two-thirds as 

 long as deep. 



The coloration is very similar to that of II. forskalii, but the black longitudinal 

 streaks are more strongly marked and extend to the series of scales below the lateral 

 line, and a deep black spot is almost constantly present on the adipose dorsal fin, even 



