1907.] AFRICAN SILURID FISHES. 1097 



pectoral spine or to base of ventral ; inner mandibular barbel |- 

 length of outer, a little shorter than the nasal. 18-20 gill-rakers 

 on first arch. Dorsal 30-32, its distance from occipital process 

 1 or i length of head ; adipose dorsal as long as or a little shorter, 

 lower than, and commencing a short distance behind, dorsal 

 proper, narrowly separated from caudal. Anal 41-46. Pectoral 

 |- length of head, the spine feebly serrated on the outer edge and 

 measuring f the length of the fin. Yentrals midway between 

 end of snout and base of caudal. Caudal a little more than 

 i length of head. Blackish brown above, whitish beneath ; fins 

 with a narrow yellowish margin. 



Total length 170 millim. 



Gold Coast. 



7. DiXOTOPTERUS. 



Boulenger, Tr. Zool. Soc. xvii. 1906, p. 550. 

 A single species. 



1. DiNOTOPTERUS CUNNINGTONI. 



Boulenger, 1. c. pi. xxxi. 



Depth of body 7-i- times in total length, length of head 3-| times. 

 Head extremely flattened, once and ^ as long as broad, its upper 

 surface covered with very thin skin and rugose with strife radiating 

 from the occipital region ; frontal fontanelle large, 2^ times as 

 long as broad, ^ length of head ; occipital fontanelle very small ; 

 a rather long and narrow occipital process ; snout broad, truncate, 

 not projecting beyond mouth ; eye small, 3 times in length of 

 snout, 7-| times in intei-orbital width ; nasal barbel f length of 

 head ; maxillary barbel a little longer than head, reaching posterior 

 third of pectoral ; outer mandibular barbels once and ^ as long 

 as inner and nearly as long as head. Jaws with bands of minute 

 villiform teeth ; similar teeth form a rather broader crescentic 

 band on the vomer. Gill-rakers very long and slender, closely 

 set, about 110 on anterior arch. Dorsal 53, its distance from 

 occipital process ^ length of head ; adipose dorsal low and short, 

 in contact with caudal. Anal 43, separated from caudal by a 

 space equal to twice diameter of eye. Pectoral i length of 

 head ; spine rather weak, not serrated, a little more than half 

 length of fin. Yentral equally distant from end of snout and 

 from root of caudal. Caudal rounded. Dark brown, almost black 

 above, pinkish white beneath. 



Described from a single specimen, 500 millim. long, the species 

 said to grow to 1290 millim. In a young specimen, 90 millim. 

 long, the head is less depressed and the eyes are proportionally 

 larger than in the adult ; ventrals a little nearer end of snout 

 than root of caudal. 



Lake Tanganyika. 



