PEOM THE LAKE NGAMI BASIN, BECHUAN ALAND. 417 



round the pupil. The second is dark brown above, shading to whitish beneath ; 

 dorsal and caudal dark olive, spotted with whitish, the former edged with purplish 

 red ; pectoral, ventral, and anal yellowish brown ; iris as in the first specimen. 



In spirit, the edge of the dorsal is yellowish {flavomarginata). 



Total length 190 to 300 mm. 



23. TiLAPIA SPAERMANI A. Smith. 



The three specimens in Mr. Woosnam's collection, of which a description follows, 

 seem to show the species T.fouloni Blgr. to be untenable. 



Depth of body 2 to 2^ times in total length, length of head 3^ to 3^ times. Head 

 If times as long as broad ; snout rounded, with slightly convex or slightly concave 

 upper profile, a little shorter than postocular part of head ; eye 4 to i^ times in length 

 of head, f to f interorbital vpidth, equal to or a little more than prseorbital depth ; 

 mouth moderate, about f width of head ; maxillary extending to between nostril and 

 eye; teeth small, in 4 to 6 series, 60 to 80 in outer series of upper jaw; 2 or 3 series 

 of scales on the cheek, the width of the scaly part less than diameter of eye. Gill- 

 rakers short, 9 to 11 on lower part of anterior arch. Dorsal XIV-XV 10-11 ; spines 

 increasing in length to the last, which measures about f length of head; longest soft 

 ray f to once length of head. Anal III 10 ; third spine longest, f to ^ length of 

 head. Pectoral a little shorter than head, not reaching vertical of origin of anal. 

 Ventral reaching origin of anal or a little beyond. Caudal rounded. Caudal peduncle 

 deeper than long. Scales granulate, not denticulated, 27-28 ^- ; lat. 1. fjEi9- 



Mr. Woosnam describes the colour as dark olive-brown, the scales Avith greenish- 

 yellow margins ; dorsal, caudal, and ventral fins olive-brown like the body, the former 

 with darker and lighter stripes, pectorals paler ; lower part of jaw and lower lip 

 tinged with greenish blue with a dash of pink ; opercular spot blue-black ; iris brown, 

 with a red-gold ring round the pupil. 



Total length 145 to 190 mm. 



24. TiLAPIA MELANOPLEURA A. Dum. 

 Chromis latus Gtlir. ; Tilapia rendalli Blgr. 



A widely distributed species in the Zambesi basin and in West Africa. 



25. TiLAPIA woosNAMi, sp. n. (Plate XLIIl. fig. 2.) 



Depth of body 2| times in total length, length of head 3 times. Head twice 

 as long as broad ; snout obtusely pointed, as long as postorbital part of head, as lono- 

 as broad, with slightly convex upper profile ; eye 4J times in length of head, equal 

 to width of interorbital region or depth of prseorbital ; mouth moderate, f width of 

 head ; maxillary extending to between nostril and eye ; teeth in outer row rather 



3l 2 



