MAECUSENIUS. 77 



37-46. Ad., hg-r., & yg. Between Luxor and Assuan. L. Loat, Esq. (C). 



47. Ad. Assuan. „ 



48. Hgr. Lake No, White Nile. 



49. Hgr. Gondokoro, Bahr-el-Gebel. „ 



16. MARCUSENIUS CASTOR. 

 Ilippnpotamyrus castor, Pappenli. Sitzb. Ges. nat. Fr. Berl. 1906, p. 260, and 

 Mitth. Zool. Mus. Berl. iii. 1907, p. 3J1, pi. ii. figs. 2 & 3. 



Depth of body equal to length of head, Sf to 4 times in total length. 

 Head 1^ to 1:^ times as long as deep, with curved upper profile ; snout 

 rounded, ^ length of head, projecting beyond mouth ; mouth below 

 nostrils, its width -j length of head ; teeth bicuspid (truncate when worn 

 down), 5 in upper jaw, 6 in lower, median pair of lower teeth much 

 larger than the others ; nostrils equally distant from end of snout and 

 from eye, on a line with lower border of eye ; eye moderate, about f 



rig. GO. 



^y^f^'f^rr^r^^;-^ 



Marcusenius castor. 

 Type. i. 



length of snout and f interorbital width. Dorsal 31-32, its origin 

 corresponding to that of anal, its length | its distance from head. 

 Anal 32-35, nearer base of caudal than base of ventral. Pectoral 

 pointed, a little shorter than head, not quite twice as long as ventral, 

 and extending beyond root of latter. Caudal densely scaled on half of 

 its surface, with pointed lobes. Caudal peduncle 3 times as long as 

 deep, I length of head. 85-93 scales in lateral line, g in transverse 

 series on body, - in transverse series between dorsal and anal, 16 round 



