OF FISHES FROM LAKE TANGANYIKA. 23 



I. Vent nearly equally distant from the end of the snout and the base of the caudal fin. 



A. Two strong prseopercular spines. 



D. XXIII-XXIV 75 ; A. II 75-76; length of head (measured to extremity of opercle and without 

 rostral appendage) hardly twice in its distance from vent and 6 times as great as its 

 distance from the first dorsal spine 1. M. marchii Sauv. 



D. XXIV 100 ; A. II 100 ; length of head 3J times in its distance from vent, equal to its distance 

 from the first dorsal spine 2. M. cryptacanthus Gthr. 



D. XXVII 85 ; A. Ill 92 ; length of head 2| in its distance from vent, 3 times as great as its 

 distance from first dorsal spine 3. M. congicus Blgr. 1 



D. XXVI-XXX80; A. 1180 4 . M . liberiensis Blgr. 8 



D. XX1X-XXX 117-130; A. II 117-127; length of head nearly 4 times in its distance from 

 vent, and nearly twice as great as its distance from the first dorsal spine. 



5. M. loennbergii Blgr. 3 



B. Prssopercular spines minute (young) or absent. 



D. XXVII-XXVIII 70-80; A. II 80-90; length of head 3 to 4 times in its distance from vent, 

 equal to or a little less than its distance from the first dorsal spine. 



6. M. flavomarginatus Blgr. 4 

 D. XXVII 80-82 ; A. II 60-65 ; length of head equal to its distance from the first dorsal spine. 



7. M. niger Sauv. 



D. XXVII-XXIX 65-70; A. II 68-75; length of head 2i to 3 times in its distance from the 

 vent, and ^ in its distance from the first dorsal spine ... 8. M. shiranus Gthr. 



D. XXIX 95 ; A. II 85 ; length of head 3 times in its distance from the vent, and ^ in its distance 

 from the first dorsal spine 9. M. nigromarginatus Blgr. 5 



D. XXV-XXVII 70-80 ; A. II 70-80 ; length of head twice in its distance from the vent, and 

 nearly ^ in its distance from the first dorsal spine .... 10. M. moorii Blgr. 



II. Vent much nearer the caudal fin than the end of the snout ; one or two prteopercular 



spines. 



D. XXX 85 ; A. II 70 11. M. marmoratus Perugia. 



D. XXXIII-XXXV 50-60 ; A. II 50-60 12. M. tanganicce Gthr. 



III. Vent much nearer the end of the snout than the caudal fin. 



D. XXXI-XXXII 103; A. I 116 13. M. ophidium Gthr. 



1 A species from the Upper Congo founded on a single specimen with mutilated tail and regenerated caudal 

 fin. I have now a perfect specimen. 



2 M. marchii Steind. nee Sauv. — Liberia. 



8 M. cryptacanthus Loennberg nee Gthr. — Cameroon. 



1 A new species founded on specimens from the Gaboon previously referred to M. cryptacanthus. 

 5 A new species founded on a single specimen from Ashantee. 



8 Type examined.- — Tent equally distant from the head and from the caudal ; head once and a hair us lung 

 as its distance from the first dorsal spine ; 17 scales between origin of soft dorsal and lateral line. 



