THE TANGANYIKA PROBLEM. 



72. TlLAPIA LABIATA. — Blgr. 1898. (Fig- p. 1 73-) 



Outer teeth rather large, feebly notched ; inner teeth very small, tricuspid, 



in 3 or 4 series. Depth of body equal to length of head, 2§ to 2| times in 



total length. Snout, with straight upper profile, \\ to if diameter of eye, which is 



3} to 4} times in length of head and equals interorbital width ; maxillary not 



extending to below anterior border of eye ; 3 or 4 series of scales on the 



cheek ; large scales on the opercle ; lips very strongly developed, both produced 



into a large triangular lobe in front. Gill-rakers moderate, 15 on lower part 



of anterior arch. Dorsal XVIII. 10 ; middle dorsal spines longest, about \ length 



of head, and a little shorter than longest soft rays. Pectoral f to £ length of head. 



Ventral reaching origin of anal. Anal III. 6-7 ; third spine longest, as long as 



longest dorsal, slightly shorter than longest soft rays. Caudal truncate. Caudal 



peduncle slightly longer than deep. Scales finely denticulate on the border, 



5 — 6 22 — 25 



33"35 " — > l at - I- — • Pale olive, with IO more or less distinct darker 



12—13 13—15 



cross-bars ; fins of greyish brown ; dorsal sometimes with oblique dark and light 



streaks ; caudal with numerous round dark spots between the rays. 



Total length, 170 millim. 



Described from four specimens from Kinyamkolo. 



This species is easily recognisable by the extraordinary development of the lips, 

 which bears a curious resemblance to that observed in the Central American Heros 

 labialus. It appears to be nearest allied to Ctenochromis tutchisquamulatits, 

 Hilg. , and C. Sauvagii, Pfeffer, from the Victoria Nyanza. 



73. TlLAPIA PLEUROTVENIA. Blgr. 1901. (Fig. p. 200.) 



Depth of body 2} to 3 times in total length, length of head 3 to 3.} times. Snout, 



with profile descending in a straight line, as long as the diameter of the eye, which 



is contained 3 \ to 3} times in length of head, and exceeds a little interocular width ; 



mouth small, its width half or a little more than half that of head, extending to below 



nostril, or between nostril and eye ; teeth very small, in 3 series, outer bicuspid ; 



3 or 4 series of scales on cheek. Gill-rakers short, 10 to 12 on lower part of 



anterior arch. Dorsal XV.-XVII. 11-12; last spine longest, a little less than 



half length of head ; longest soft rays § length of head. Pectoral pointed, a little 



shorter than the head, not quite reaching origin of anal. Anal III. 8-10 ; third 



spine a little shorter than last dorsal spine. Caudal deeply notched and crescentic. 



Caudal peduncle i4 as long as deep. Scales very thin, without denticulation, 



4 22 — 24 



32-35 ! lat. 1. — . Pale brown above, white beneath; a blackish 



JJ 11 — 12 10 — 15 



lateral stripe, from the opercle to the caudal ; fins greyish ; small, round, white spots 



on soft dorsal and caudal. 



Total length, no millim. 



Described from several specimens from the north end of Lake Tanganyika, and 

 from the mouth of the Rusisi River. 



