1907.] AFRICAX SILURID FISHES. 



1095 



1 Heterobranchus bidorsalis. 



I. Geofi'roy, Descr. Egypte, Poiss. p. 305, pi. xvi. figs. 2 & 5, 

 & pi. xvii. fio'S. 8 & 9 (1827); Giinther, Petherick's Trav. ii. 

 p. 220 (1869)'; Bouleng. Fish. Nile, p. 300, pi. liv. fig. 1 (1907). 



Heterohranchus geofroyi Ouvier & Yaleiiciennes, Hist. Poiss. 

 XV. p. 392 (1840). 



Heterohranchus senegcdensis Ouvier & Valenciennes, t. c. p. 39/ ; 

 Steindachner, Sitzb. Ak. Wien, Ix. 1869, p. 980. 



Heterohrandms intermedms Giinther, Cat. Fish. v. p. 22 (1864); 

 and 1. c. 



Depth of body 6 to 9 times in total length, length of head 2i to 

 3i times. Head very strongly depressed, ![ to li_ times as long 

 as broad, its upper surface coarsely granulate in the adult ; 

 occipital process pointed, sometimes very obtusely; frontal 

 fontanelle knife-shaped, 3 to 4 times as long as broad, 3 to 5 

 times in length of head ; occipital fontanelle small, in advance 

 of occipital process ; eye 3 (young) to 61 times in length of snout, 

 6 to lOi- times in interorbital width ; width of mouth a little less 

 than interorbital width ; liand of p]'a?maxillary teeth about 5 

 times as long as broad ; vomerine teeth also villiform, forming 

 a crescentic band which is 1^: to U times as broad as the prte- 

 maxillary band and may have a small central posterior process ; 

 nasal barbel f to once length of head ; maxillary barbel 4 to once 

 and -f length of head, extending to extremity of pectoral or between 

 this point and root of ventral ; outer mandibular barbel lyL to 1} 

 times as long as inner, which measures 1 to 1-|- times length of 

 head. Gill-rakers rather short, 20 to 30 on anterior arch. 

 Dorsal 38 to 45, its distance from occipital process y^ *<^ i 

 length of head ; adipose dorsal i- to f as long as, as deep as or 

 lower than, and commencing immediately behind, rayed dorsal, 

 extending to base of caudal. Anal 50 to 57, extending to base of 

 caudal. Pectoral fin |- to ^ length of head, the spine smooth and 

 measuring f to f the length of the fin. Yentral midway between 

 end of snout and base of caudal, or a little nearer the latter. 

 Caudal i to Jj- length of head. Dark olive above, whitish beneath ; 

 a dull orange or red edge to the dorsal, adipose, and caudal fins. 

 Total lengtl^ ^70 millim. ; grows to 1220. 

 Nile, Chad Basin, Senegal, Niger. 



2. Heterobeanchus lo^tgifilis. 



Ouvier & Valenciennes, Hist. Poiss. xv. p. 394, pi. ccccxlvii. 

 (1840) ; Giinther, Oat. Fish. v. p. 22 (1864), and Petherick's Trav. 

 ii. p. 221 (1869) ; Boulenger, Fish. Nile, p. 303, pi. liv. fig. 2 



(1907). 



Heterohranchus laticejjs Peters, Mon. Berl. Ac. 18o2, p. 682, 

 and Reise Mossamb. iv. p. 37, pi. vii. fig. 1 (1868); Boulenger, 

 Poiss. Bass. Congo, p. 265 (1901). 



Depth of body 6 to 8 times in total length, length of head 3 to 

 3| times. Head less strongly depressed than in the preceding 



