NOTOPTERUS. — XENOMYSTUS. 147 



Lateral line 130-165. Olive-grey to blackish, with more or less d stinc. 

 darker spots or marblings, sometimes enclosing lighter roundish spots on 

 the body or on the anal fin. 



Total length 570 millim. 



Gambia to Congo. 



1-2. Ad. Gaml)ia. J. S. Budgett, Esq. (P.). 



15— i. Hot., types. Sierra Leone. 



5. Ad., type. Niger. A. ^Murray, Escj. (P.). 



6. Hgr., type. „ Mr. J. T. Daltou (C). 

 7-8. Hgr., skins, types. « 



9-10. Yg. Oouta, Lower Niger. Dr. W. J. Ansorge (C). 



11. Ad. S;ij)elle, „ „ 



12. Hgr. „ „ I\Ir. J. I). Hanilyn (C.) ; 



Hon. W.Rothschild (P.). 



13. Ad. Old Oalal)ar. Miss Kingsley (C). 



14. Skel. ,, ,, 



15. Ad. Ibali, L. Leopold II., Congo. M. P. Delhcz (C). 



2. XENOMYSTUS. 



Giinth. Cat. Fish. vii. p. 479 (1808) ; Bouleng. Poiss. Bass. Congo, p. 118 (1901), 

 and Fish. Nile, p. 80 (1907). 



Differing from the preceding in the absence of dorsal fin and the 

 presence of only 3 branchiostegal rays. 

 A single species. 



1. XENOMYSTUS NIGRL 



Notopterus nigri, Giinth. Cat. Fish. vii. p. 481 (1868). 



Botopterus {Xenomyslus) nili, Steind. Sitzb. Ak. Wien, Ixxxiii. i. 1881, p. 19G, 



pi. iv. fig. 2. 

 Notopterus (Xenonv/stus) nigri, Steind. Notes Leyd. Mus. xvi. 1894, p. 85. 

 Xenomystus ni(jri, Boulenf^. Poiss. Bass. Con^o, p. 118 (1901); Werner, Sitzl). Ak. 



Wien, cxv. i. 190G, p. 1124 ; Bouleng. Fish. Nile, p. 80, pi. xv. fig. 1 (1907). 



Depth of body 4-j to 5 times in total length, length of head 6 to 7|- 

 times. Snout very short, shorter than eye, the diameter of which is 

 3 to 3J times in length of head and equals or nearly equals interocular 

 width ; mouth extending to below anterior third or centre of eye ; 

 nasal tentacle long and attenuate, f to f diameter of eye; proeorbital, 

 suborbitals, prseoperculum, and mandible with the edge strongly 

 serrated; prEeopercnlum with a serrated ridge, parallel with the lower 

 border. Gill-membranes extending without a notch across the isthmus. 

 Gill-rakers very short, tubercular, 9 to 1 1 on lower part of anterior arch. 



l2 



