674 MR. G. A. BOULENGER ON 



6. Barbus erlangeri Blgr. 



Also from the hot springs at Chandler Falls, upper Eusso ISTyiro, 

 and from the Saya. 



7. Barbus nairobiensis Blgr. 



From the Eusso Nyiro above the falls. 



8. Barbus percivali Blgr. 



Fi-oni the above locality, and also from the Saya. 

 The largest specimen measures 105 mm. 



9. Barbus argyrot^nia, sp. n. (PI. LXXIX. fig. 1.) 



Depth of body 2| to 3 times in total length, length of head 31 

 to 3| times. Snout rounded, shorter than the eye, which is 2| to 

 3 times in length of head and equals or nearly equals interorbital 

 width ; mouth small, subinferior ; lips feebly developed ; two 

 barbels on each side, anterior about | diameter of eye, posterior 

 as long as or slightly longer than eye. Dorsal III 8, equally 

 distant from posterior border or centre of eye and from base of 

 caudal, border feebly concave; last simple ray enlarged, bony, 

 strongly serrated behind. Anal III 5, not reaching caudal. 

 Pectoral a little shorter than head, not reaching ventral ; base of 

 latter below origin of dorsal. Caudal peduncle a little longer 

 than deep. Scales radiately striated, 30-31 g|, 3 between lateral 

 line and ventral, 14-16 round caudal peduncle. Pale sand colour, 

 with a silvery lateral band which is sometimes edged above with 

 a streak of black pigment; fins white, often tinged with pale 

 orange at the base. 



Total length 53 mm. 



Numerous specimens from the Eusso Nyiro below the falls, 

 B. argyrotcenia stands nearest to B. zanziharicus Peters. 



10. Barbus mimus, sp. n. (PI. LXXIX. fig. 2.) 



Depth of body 2| to 2| times in total length, length of head 

 3| to 4 times. Snout rounded, much shorter than the eye, which 

 is 2| to 3 times in length of head and equals interorbital width ; 

 mouth small, subinferior ; lips feebly developed ; two barbels on 

 each side, anterior about | diameter of eye, posterior a little 

 longer than eye Dorsal III 8, equally distant from posterior 

 border or centre of eye and from base of caudal, border feebly 

 concave; last simple ray not enlarged, not serrated, as long as or 

 a little longer than head. Anal III 5, not reaching caudal. 

 Pectoral as long as head, not quite reaching ventral; base of 

 latter below origin of dorsal. Caudal peduncle as long as deep or 

 a little longer than deep. Scales radiately striated, 25-26 % 2-2| 

 between lateral line and ventral, 12 round caudal peduncle. 

 Pale sand-colour, with a silvery lateral band, which is sometimes 



