112 MR. G. A. BOULBNGER ON THE AFRICAN AITD [Feb. 7, 



III (rarely IV) 9-10 ; third spine a little shorter but stronger 

 than last dorsal spine. Caudal rounded. Caudal peduncle as long 



as deep. Scales cycloid, 30-33 jfii|; lat. 1. j^j^. Brownish or 

 olive, vertical fins and ventrals darker. 



Total length 270 millim. 



East Africa, from the Coast of Zanzibar to the Zambesi. 



5. TiLAPIA NILOTICA. 



Lahrus niloticus, Linn, in Hasselq. Iter Palaest. p. 346 (1757), 

 and S. N. i. p. 477 (1766) ; Sonnini, Voy. Egypte, ii. p. 395, 

 pi. xxvii. fig. 1 (1799). 



Chromis nilotica, Cuv., Guerin, Icon. R. An. i. Poiss. pi. xliv. 

 fig. 1 (1844); Sauv. Bull. Soc. Philom, (7) iv. 1880, p. 211; 

 Lortet, Ann. Mus. Lyon, iii. 1883, p. 137, pi. vii. ; Mitchell, Rep. 

 Pish. L. Menzaleh, p. 12, pi. ii. (1895) ; Giinth. Proc. Zool. Soc. 

 1896, p. 218. 



Chromis niloticus, part., Giiuth. Cat. iv. p. 267 (1862), and 

 Proc. Zool. Soc. 1864, p. 490 ; Steind. Verb, zool.-bot. Ges. Wien, 

 xiv. 1864, p. 226; Peters, Reise Mossamb. iv. p. 23 (1868); 

 Giinth. in Petherick, Trav. C. Afr. ii. p. 216 (1869) ; Steind. Sitzb. 

 Ak. Wien, Ix. 1870, p. 96 ; Pfeffer, Jahrb. Hamb. vAm. Anst. x. 

 1893, p. 149 ; Vinciguerra, Ann. Mus. Geneva, (2) xv. 1895, p. 28 ; 

 Pfeffer, Thierw. O.-Afr., Fische, p. 10 (1896). 



Chromis giwntkeri, Steind. Verb, zool.-bot. Ges. Wien, xiv. 1864, 

 p. 228, pi. viii. figs. 3 & 4. 



Chromis spilunis, Giinth. Proc. Zool. Soc. 1894, p. 89, pi. x. 

 fig. A, and 1896, p. 219. 



Tilaina nilotica, Bouleng. Tr. Zool. Soc. xv. 1898, p. 6. 



Teeth veiy small, in 4 to 6 series in both jaws. Depth of body 

 2^ to 2| times in total length, length of head 2| to 3| times. 

 Snout with nearly straight upper profile, I5 to Ig diameter of eye 

 (shorter in the young), which is 4| to 6 times in length of head 

 (3g to 3| in the young), and Ig to 2| times in interorbital width ; 

 mouth moderate, ^ to § width of head, extending to below 

 anterior border of eye or between the nostril and the eye ; 2 or 3 

 series of scales on the cheek, forming, under the eye, a nearly 

 straight horizontal band which equals or exceeds the width of 

 the naked prseopercle; large scales on the opercle. Gill-rakers 

 short, 17 to 23 on lower part of anterior arch. Dorsal XV-XVIII 

 11-13 ; last spine longest, f to | length of head, f to § length of 

 longest soft rays. Pectoral falciform, 1 to l:j length of head, 

 extending as far as origin of anal or a little beyond. Ventral 

 reaching vent or anal. Anal III 9-11 ; third spine as long as or 

 a little shorter than longest dorsal spine. Caudal rounded. 

 Caudal peduncle slightly deeper than long. Scales cycloid, 31-35 

 rt£- • lat. 1. ^1^^. Olive, some or most of the scales darker at the 



14:— 10 ' LO—X.'i 



base, or lighter and golden in the centre ; vertical fins with blackish 

 and whitish spots forming transverse or oblique streaks ; a blackish 

 opercular spot ; young with 8 or 9 more or less distinct dark bars 



