i6o 
THE TANGANYIKA PROBLEM. 
the eye, which is contained 4 to 4^ times in the length of the head ; interorbital 
width a little greater than the diameter of the eye ; mouth extending to below the 
anterior third or the centre of the eye ; no barbels ; the naked space between the 
pneopercle and the suborbitals less than half the width of the latter. Gill-rakers 
very short, almost rudimentary, Son lower part of anterior arch. Dorsal III. 9, 
originating at equal distance from the anterior border of the eye and the root of the 
caudal ; its border is not notched, and its depth equals about 3 the length of the 
head. Anal III. 13-14, originating under the middle of the dorsal ; its anterior 
rays a little longer than those of the dorsal and much longer than the posterior rays, 
forming a rounded lobe. Pectoral pointed, shorter than the head, not reaching the 
ventral, which extends to the origin of the anal. Caudal forked. Caudal peduncle 
twice as long as deep. Scales 56-60 , 3 between the lateral line and the root 
of the ventral. Silver)', brownish on the back ; more or less distinct dark vertical 
bars on the side of the body, about 10 in number ; dorsal blackish at the end. 
Total length, 115 millim. 
Several specimens from the north end of Lake Tanganyika. 
13. Barilius tanganica:. — Blgr. 1900. (Fig., p. 165.) 
Depth of body equal to length of head, 4j times in total length. Head a little 
over twice as long as broad, with straight declivous upper profile ; snout very 
pointed, not extending below the lower jaw, once and a half the diameter of the 
eye, which is contained 53 times in the length of the head ; interorbital width once 
and a half the diameter of the eye ; mouth extending to below the posterior border 
of the eye ; no barbels ; the naked space between the praeopercle and the subor- 
bitals about 3 the width of the latter. Gill-rakers short, 10 on lower part of 
anterior arch. Dorsal III. 10, originating at equal distance from the occiput and 
the root of the caudal, the posterior third of its base above the anal ; its anterior 
rays are longest, measuring a little more than half the length of the head. Anal 
III. 17, strongly notched, with rounded anterior lobe, the longest rays of which 
measure J the length of head, whilst the posterior rays measure barely \ . Pectoral 
pointed, | length of head, not reaching the ventral, which extends to the vent. 
Caudal forked. Caudal peduncle a little over twice as long as deep. Scales 
82 — , 4 between the lateral line and the root of the ventral. Silvery, olive on 
back; 16 or 17 blackish vertical bars on each side of the body, equally distant 
from the median dorsal line and from the lateral line. 
Total length, 260 millim. 
Described from a single specimen from north end of Lake Tanganyika. 
SILURIFLE. 
14. Clarias robecchii. — Vincig. 1893. 
