STNODONTIS. 383 



13. SYNODONTIS MEMBRANACEUS. 



(Plate LXXV.) 



Pimelodus rne'mbranaceus, Geoffroy, Descr. Egypte, Poiss. pi. xiii. figs. 1 & 2 (1809). 



Synodontis membranaceus, part., I. Geoffroy, op. cit. p. 297 (1827); Ouvier & Valenciennes, Hist. 



Poiss. xv. p. 258 (1840) ; Steindaehner, Sitzb. Ak. Wien, lxi. i. 1870, p. 536. 

 Hemisynodontis membranaceus, Bleeker, Nederl. Tijdschr. Dierk. i. 1863, p. 55. 

 Synodontis membranaceus, Giinther, Cat. Fish. v. p. 215 (1864), and Petherick's Trav. ii. p. 236 



(1869) ; Steindaehner, Sitzb. Ak. Wien, lxxxiii. i. 1881, p. 200; Boulenger, Ann. & Mag.N. H. 



(7) viii. 1901, p. 12. 

 Synodontis guentlieri, Vaillant, Bull. Soc. Philom. (8) v. 1892, p. 16, and N. Arch. Mus. (3) viii. 



1896, pp. 164 & 167. 



Body strongly compressed, its depth twice and two-thirds to three and one-third 

 times in the total length, the length of the head twice and a half to three times. Head 

 once and one-fourth to twice 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 

 shorter than the postocular part of the head ; eye superolateral, four (young) to six 

 and a half times in the length of the head, not less than the interorbital width in the 

 young, once and a half to twice in the interorbital width in the adult ; interorbital 

 region convex; occiput tectiform. Mouth large, with feeble lips, except on the sides, 

 where they are confluent with the membrane of the maxillary barbel and supported by 

 a barbel-like dermal ray which extends to its extremity ; praemaxillary teeth very feeble, 

 forming a short and rather narrowband; mandibular teeth very minute, 8 to 14 in 

 number, forming a small patch at the symphysis of the lower jaw. Maxillary barbel 

 with a very broad membranous border almost to its extremity, as long as or a little 

 longer or a little shorter than the head, reaching the root of the pectoral spine or a 

 little beyond ; mandibular barbels inserted on a straight transverse line, with a few 

 long, slender branches in the basal half, with a membranous border in the terminal 

 half, the inner one-third to two-thirds the length of the outer. Gill-openings separated 

 on the throat by a narrow isthmus, the width of which is less than the diameter of the 

 eye. Occipito-nuchal shield rough like the occiput, tectiform, once and a half to twice 

 as long as broad, the posterior processes obtuse or truncate. Humeral process 

 subtriangular, flat, granulate, as long as deep or deeper than long, 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 curved, smooth in front, feebly serrated behind, 

 three-fifths to four-fifths the length of the head. Adipose dorsal fin three to five 

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



