DISTICHODUS. 141 



1. DISTICHODUS NILOTICUS. 

 (Plate XXII. and Plate XXIII. fig. 1.) 



Salmo niloticus, part., Linnaeus, in Hasselquist, Peise Palsest. p. 422 (1762). 



Salmo cegyptiacus, part., Gmelin, Sjst. Nat. i. p. 1386 (1788). 



Characinus nefasch, part., Lacepede, Hist. Poiss. v. p. 274 (1803) ; Geoffroy, Descr. Egypte, 



Poiss. p. 44 Q809). 

 Citharinus nefasch, part., Piippell, Beschr. n. Fische Nil, p. 5 (1829). 

 Distichodus niloticus, Miiller & Troschel, Hor. lchthyol. i. p. 12, pi. i. fig. 3 (1845) ; Giinther, Cat. 



Fish. v. p. 360 (1864), and Petherick's Trav. ii. p. 246 (1869) ; Boulenger, Ann. & Mag. N. H. 



(7) viii. 1901, p. 513. 

 Distichodus nefasch, part., Cuvier & Valenciennes, Hist. Poiss. xxii. p. 175 (1849). 

 Distichodus rodolphi, Giinther, Proc. Zool. Soc. 1896, p. 223 ; Yinciguerra, Ann. Mus. Genova, 



(2) xix. 1898, p. 258. 



Depth of body two and a half to three and three-fifths times in the total length, 

 length of head three and one-fourth (young) to five and one-eighth times. Head once 

 and one-third to once and a half as long as deep, once and two-thirds to twice and 

 a half as long as broad ; snout rounded, somewhat depressed, projecting more or less 

 beyond the mouth, its length less than the interorbital width ; diameter of eye three 

 (young) to six times in the length of the head, interorbital width two and one-fourth 

 to three times ; width of mouth three and three-fourths to four and two-thirds times in 

 the length of the head ; teeth in two series in each jaw, the outer series containing 24 

 (young) to 36 teeth ; maxillary extending to below the nostrils ; upper surface of head 

 and opercle more or less rugose, with radiating striae. Gill-rakers short, 17 to 20 on 

 lower part of anterior arch. Dorsal fin with 22 to 26 rays, 3 to 6 of which are 

 unbranched, equally distant from the occiput and from the root of the caudal fin, or a 

 little nearer the former ; longest rays two-thirds to three-fourths the length of the head. 

 Adipose fin small, nearly equally distant from the rayed dorsal and from the caudal. Anal 

 fin with 13 to 15 rays, 3 or 4 of which are unbranched; longest ray one-half to three- 

 fourths the length of the head, usually reaching, or even extending a little beyond, the 

 root of the caudal fin. Pectoral fin three-fifths to five-sixths the length of the head, 

 as long as or slightly shorter than the ventral. Caudal fin forked, with rounded 

 lobes. Caudal peduncle as long as deep or slightly deeper than long. Scales 

 90-110 20E05' 15 to 18 between the lateral line and the ventral fin. 



Purplish grey above, silvery white below ; young with 10 to 13 vertical dark bars 

 on the body, a round blackish spot above the pectoral fin, on or below the lateral line, 

 and another at the base of the caudal fin, these markings disappearing gradually with 

 age ; vertical fins greyish, sometimes blackish at the edge, the dorsal with numerous 

 small round darker spots. Iris light bronze-brown. 



