160 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 

 prseopercle and the suborbitals less than half the width of the latter. Gill-rakers 

 very short, almost rudimentary, 8 on 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 \ 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. Silvery, 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 million. 



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 5^ 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 prseopercle and the subor- 

 bitals about \ 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 % the length of head, whilst the posterior rays measure barely \. Pectoral 

 pointed, f 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. Silver}', olive on 



7 

 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. 



silurim:. 



14. Clarias robecchii. — Vincig. 1893, 



