380 



SILURIML 



12. SYNODONTIS BATENSODA. 

 (Plate LXXIV.) 



Synodontis membranaceus, part., I. Geoffroy, Descr. Egypte, Poiss. p. 297 (1827) ; Cuvier & 

 Valenciennes, Hist. Poiss. xv. p. 258 (1840) ; Steindachner, Sitzb. Ak. Wien, lxi. i. 1870, 

 p. 536. 



Synodontis batensoda, Riippell, Fortsetz. Beschr. n. Fische Ml, p. 6, pi. iii. fig. 2 (1832) ; Boulenger, 

 Ann. & Mag. N. H. (7) viii. 1901, p. 12. 



Br achy synodontis batensoda, Bleeker, Nederl. Tijdschr. Dierk. i. 1863, p. 55. 



Synodontis melanogaster, Ehrenberg, in Peters, Peise n. Mossamb. iv. p. 31 (1868). 



Synodoiitis membranaceus, Vaillant, N. Arch. Mus. (3) viii. 1896, pp. 161 & 167. 



Body strongly compressed, its depth twice and two-thirds to three times in the 

 total length, the length of the head twice and two-thirds to three and one-third times. 

 Head once and one-fourth to once and three-fourths as long as broad, deeper than 

 broad, rugose, granulate above from between the eyes, the granulate area sometimes 

 extending a little on the snout ; frontal fontanelle narrow ; snout obtusely pointed, as 

 long as or a little longer than the postocular part of the head ; eye supero-lateral, three 

 and a half (young) to five and one-third times in the length of the head, not less than 

 the interorbital width in the young, once and a half to once and two-thirds in the 

 interorbital width in the adult ; interorbital region convex ; occiput obtusely tectiforra ; 

 operculum terminating in a few short spines. Mouth moderate, with moderately 

 developed lips; prsemaxillary teeth forming a short and broad band; movable mandi- 

 bular teeth one-fourth to one-third the diameter of the eye, 30 to 57 in number. 

 Maxillary barbel with a broad marginal membrane, three-fifths to about once the 

 length of the head, usually reaching the base of the pectoral spine or a little beyond ; 

 mandibular barbels inserted on a straight transverse line, the outer with long, slender, 

 simple branches, once and one-third to twice as long as the inner, some of the branches 

 of which are bifid or trifid. Gill-openings extending downwards beyond the base of 

 the pectoral fin, but separated by a broad isthmus, which at least equals the interorbital 

 width. Occipito-nuchal shield rough like the occiput, obtusely tectiform, once and a 

 half to twice as long as broad, the posterior processes pointed or rounded. Humeral 

 processes about as long as broad, flat, granulate, pointed or obliquely truncate 

 posteriorly, not extending as far back as the occipito-nuchal process. Skin smooth, 

 not villose. Dorsal fin with I 7 rays, the spine strong, straight or feebly curved, 

 smooth in front, feebly serrated behind, about as long as the head, the soft terminal 

 part produced into a short filament. Adipose dorsal fin twice and a half to four times 

 as long as deep, originating immediately behind the rayed dorsal. Anal fin acutely 

 pointed, with 12 to 14 rays, 7 to 9 of which are branched. Pectoral spine as long as 



