STNODOKTIS. 



475 



Depth of body 2§ to 3^ times in total length, length of head 2^ to 

 3 times. Head 1 j to 2 times as long as broad, rugose, granulate above 

 from between the eyes, the granulate area sometimes extending a little 

 on the snout ; snout obtusely pointed, as long as or a little shorter than 

 postocular part of head ; eye supero-lateral, 4 (young) to 6^ times in 

 length of head, not less than interorbital width in young, 1J to 2 times 

 in interorbital width in adult. 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 ; preemaxillary teeth very feeble, forming a short and rather 

 narrow band ; mandibular teeth very minute, 8 to 14 in number, forming 



Fitr. 355. 



Synodontis membranaceus. 

 Khartum (F. X.). 3. 



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 head, reaching root of pectoral spine 

 or a little beyond ; mandibular barbels inserted on a straight transverse 

 line, with a few long, slender branches in basal half, with a membranous 

 border in terminal half, inner ^ to § length of outer. Gill-openings 

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

 than diameter of eye. Occipito-nuchal shield rough like the occiput, 

 tectiform, 1^ to 2 times as long as broad, posterior processes obtuse or 

 truncate. Humeral process subtriangular, flat, granulate, as long as 

 deep or deeper than long, not extending so far back as occipito-nuchal 



