PETROCEPHALUS. 



preserved, in the Paris Museum. They measure from 83 to 100 millimetres. I have 

 noted 22-26 dorsal and 30-33 anal rays, and scale formula : 38-40 f^, jy^, 12. 



Measurements (in millimetres) and numbers of Jin-rays and scales. 



Total length (without caudal fin) 



Greatest depth o£ body .. 



Length of head 



Width of head 



Length of snout 



Diameter of eye 



Interocular width 



Width of mouth 



Length of caudal peduncle 



Depth of caudal peduncle . . . . 



Length of pectoral fin 



Number of rays in dorsal fin 



„ anal fin 



scales in lateral line 



from the middle of the back to the lateral line . 

 „ lateral line to the middle of the belly . 



between dorsal fin and lateral line 



„ lateral line and anal fin 



round caudal peduncle 



1. 



2. 



3. 



4. 



5. 



90 



88 



75 



72 



57 



30 



28 



25 



23 



17 



23 



22 



19 



18 



14 



11 



11 



9 



9 



7 



4 



4 



4 



3 



2 



5 



5 



5 



5 



4 



7 



8 



7 



7 



5 



6 



6 



5 



5 



4 



15 



17 



14 



13 



11 



6 



7 



5 



5 



4 



16 



18 



15 



14 



11 



24 



23 



23 



25 



24 



34 



32 



32 



35 



30 



42 



41 



40 



41 



41 



9 



10 



9 



10 



10 



14 



11 



12 



12 



12 



10 



10 



10 



11 



11 



10 



10 



9 



10 



11 



f io 



1 

 1 



12 



12 



10 



12 



1, 3, 5. Kaedi, Senegal. — Delhez. 



2. Kafr-el-Zayat, Nile. — Loat. 



4. Gambia. — Budgett. 



Considering that this little Mormyr is found also in the Senegal and in the Gambia, 

 it is very remarkable that it should be restricted to the Lower Nile. It will probably 

 some day be found to have a much more extended distribution in the Nile. 



