PEOM THE LAKE NGAMI BASIN, BECHUANALAND. 411 



rays ; pectorals greyish olive ; ventrals greyish olive or blackish. " Iris brown over 

 mauve, with a thin silver ring round pupil." 



Total length 220 mm. 



This species is barely distinguishable from the preceding by the larger eye and the 

 smaller scales on the cheek, which form 5 instead of 3 or 4 series. 



17. Paeatilapia gibbiceps, sp. n. (Plate XLIII. fig. 1.) 



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

 twice as long as broad, upper profile very convex above the eye, jaws equal in front; 

 snout rounded, a little broader than long, shorter than postocular part of head ; eye 4-^ 

 to 4^ times in length of head, Ij times in interorbital width, equal to prseorbital width ; 

 mouth extending to below anterior border of eye ; teeth in outer series rather small, 

 about 30 on each side of upper jaw, followed by two series of minute teeth ; 4 series 

 of scales on the cheek, the vertical diameter of the scaly part a little greater than 

 diameter of eye. Gill-rakers short, posterior T-shaped, 10 or 11 on lower part of 

 anterior arch. Dorsal XV 12-13; spines increasing in length to the last, which is 

 ■| length of head, longest soft ray nearly as long as head. Anal 111 10 ; third spine 

 longest, f length of head. Pectoral as long as head, reaching vertical of origin of 

 anal. Ventral reaciiing beyond origin of anal. Caudal rounded. Caudal peduncle 

 a little deeper than long. Scales feebly rugose, not denticulated, 31-33 '^ ; 



lat. 1. 1^14. 



Mr. Woosnam's coloured sketch of the fish (native name : Nchu) shows it to be 

 olive above, pale green beneath ; a purplish-brown bar at the base of the scales ; 

 pectoral pale olive, ventral dark olive ; dorsal, anal, and caudal greyish ; dorsal edged 

 with red, the soft part with regular series of round purplish-brown spots ; similar spots 

 on the caudal ; anal with round pink spots. 



Total length 200 mm. 



Two specimens. 



18. Paeatilapia longimanus, sp. n. (Plate XL.) 



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

 2 to 2\ times as long as broad, upper profile straight or slightly concave ; lower jaw 

 slio-htly projecting beyond upper; snout obtusely pointed, as long as broad, shorter 

 than postocular part of head ; eye 4 to 5 times in length of head, equal to or slightly 

 greater than interorbital or prseorbital width ; mouth extending to below anterior 

 border of eye; teeth in outer series small, 26 to 30 on each side of upper jaw, followed 

 by one or two series of smaller teeth ; 5 or 6 series of scales on the cheek, the vertical 

 diameter of the scaly part equal to or a little greater than diameter of eye. Gill-rakers 

 short, posterior truncate or T-shaped, 9 to 11 on lower part of anterior arch. 



