318 SILUEIDtE. 



5. SILURANODON. 



Bleeker, Acta Soc. Sc. Ind.-Neerl. iv. 1858, p. 255, and Nederl. Tijdschr. Dierk. i. 1863, p. 115 ; 

 Giinther, Cat. Fish. i. p. 55 (1864). 



Body elongate, very strongly compressed, the prsecaudal region very short. A very 

 small rayed dorsal fin, without spines ; no adipose fin ; anal fin much elongate, extending 

 from the ventrals to the caudal. Pectoral fin with a spinous ray. Ventral fin small, 

 with 6 rays. No teeth. Eye large, with free border, on a level with the mouth. 

 Nostrils rather close together. Four pairs of barbels : nasal, maxillary, and two 

 mandibulars. Gill-membranes free, deeply notched. Air-bladder large and free. 



The skeleton resembles that of Eutropins and Schilbe, but the occipital process is 

 shorter and does not extend to the interneurals of the dorsal fin, the clavicular arch 

 is much more developed, its width at the symphysis being three-fourths of its transverse 

 width, and the vertebrae number only 51, viz. 11 praecaudal and 40 caudal ; 10 branchio- 

 stegal rays. 



As in Eutropins and Schilbe, the end of the caudal region is bent downwards. 



The males have a long, pointed anal papilla. 



This very remarkable genus is represented by a single species, confined to the Nile. 



1. SILURANODON AURITUS. 

 (Plate LVI. fig. 2.) 



Silurus auritus, I. Geoffroy, Descr. Egypte, Poiss. p. 289, pi. xi. figs. 1 & 2 (1827) ; Cuvier & 



Valenciennes, Hist. Poiss. xiv. p. 368 (1839). 

 Schilbe auritus, Riippell, Beschr. n. Fiscke Nil, p. 5 (1829). 

 Oued denne, Eifaud, Voy. Egypte, pi. cc. (1830). 

 Siluranodon auritus, Bleeker, Act. Soc. Sc. Ind.-Neerl. iv. 1858, p. 256 ; Giinther, Cat. Fish. v. 



p. 55 (1864), and Petherick's Trav. ii. p. 226 (1869). 



Depth of body four to five times in the total length, length of head five to six times. 

 Head once and one-third to once and a half as long as broad ; snout broad, rounded, 

 as long as the eye ; lower jaw usually projecting ; eye infero-lateral, better visible from 

 below than from above, its diameter four to four and a half times in the length of the 

 head and once and three-fourths to three times in the interocular width ; latter greater 

 than the width of the mouth. Nasal barbel nearly as long as or a little longer than 

 the head ; maxillary barbel once and one-fourth to once and two-thirds the length of 



