324 silukid^:. 



1. BAGRUS BAYAD. 

 (Plate LVII.) 



Silurus bajad, Forskal, Descr. Aniin. p. 66 (1775). 



Porcus bayad, L Geoffroy, Descr. Egypte, Poiss. p. 303, pi. xv. figs. 1 k 2 (1827). 



Bagrus bayad, Ruppell, Beschr. n. Fische Nil, p. 5 (1829) ; Cuvier & Valenciennes, Hist. Poiss. 



xiv. p. 397 (1839); Giinther, Cat. Fish. v. p. 69 (1864), and Petherick's Trav. ii. p. 227 



(1869). 

 Bagara Bachika, Rifaud, Voy. Egypte, pi. cxciv. (1830). 



Depth of body four and one-fourth to five and two-thirds times in the total length, 

 length of head three and one-third to four times. Head much depressed, once and three- 

 fifths to once and three-fourths as long as broad, smooth above or finely striated on 

 the sides of the elongate fontanelle ; occipital process long and narrow, in contact 

 with the first interneural bone, which is hidden under the skin ; snout broadly 

 rounded or truncate, projecting beyond the lower jaw, once and two-thirds (young) 

 to three and two-thirds times as long as the eye, which is four and a half (young) to 

 eleven times in the length of the head and once and a half to three and two-thirds 

 times in the interocular width ; width of mouth twice and one-fifth to twice and two- 

 thirds in the length of the head ; praemaxillary band of teeth six or seven times as long 

 as broad, a little shorter than and about as broad as or a little narrower than the band of 

 vomerine teeth. Nasal barbel one-fourth (adult) to three-fifths the length of the head; 

 maxillary barbel twice (adult) to three and one-third times the length of the head, reaching 

 the extremity of the ventral fin or the anal fin in the adult, the caudal peduncle or the 

 caudal fin in the young; outer mandibular barbel once and a half to twice the length 

 of the inner, and two-fifths to two-thirds the length of the head. Gill-rakers rather 

 long, widely set, 11 to 16 on lower part of anterior arch. Dorsal fin with I 9 to 11 

 (usually 10) rays, the last behind the vertical of the inner ray of the ventral fin; spine 

 smooth, moderately strong, one-half to three-fifths the length of the head ; anterior soft 

 rays more or less produced into filaments. Adipose dorsal fin three and a half to five 

 times as long as deep, about twice as long as the rayed dorsal, from which it is 

 narrowly separated. Anal fin with 13 to 15 rays, 9 to 10 of which are branched. 

 Pectoral fin two-fifths to one-half the length of the head, its spine moderately strong, 

 feebly serrated on the inner side. Ventral fin nearly equally distant from the end 

 of the snout and from the root of the caudal fin. Caudal fin deeply forked, each 

 lobe produced into a long filament. Caudal peduncle a little longer than deep. 



Mr. Loat describes the colour of young specimens as pale silvery grey above and 

 white beneath, slightly shot with green and gold in places, the fins colourless. The 

 upper parts are darker in adult specimens, and, as shown by a coloured sketch made by 



