FRESH-WATER FISHES OF LIBERIA—SCHULTZ 307 
Family MORMYRIDAE 
KEY TO THE GENERA AND SPECIES OF MORMYRIDS REPORTED FROM LIBERIA 
la. Length of base of anal fin contained 234 times in length of base of dorsal fin; 
depth 4 to 414; head 324; dorsal 58 to 61; anal 21 to 24; pectoral 14 or 
15; scales in lateral line about 80, but about 100 to 115 rows crossing body 
above the laterial line from gill opening to base of caudal fin; 11 or 12 
scales around caudal peduncle; snout and mouth rounded, a little elongate 
and slightly curved downward; eye 3 in snout; snout 2% in head; least 
depth of caudal peduncle 414 in its length (base of anal to midbase of 
caudal fin) ; length of caudal peduncle 1% in head. 
Mormyrus goheeni Fowler 
1b. Base of anal fin longer, contained fewer than 2 times in length of base 
of dorsal fin. 
2a. Teeth, 10 or more in both jaws and arranged in a single row. 
3a. Mouth terminal, but a little inferior; dorsal fin base contained 134 to 1% 
in base of anal fin; posterior nostril about 1 eye diameter in front 
of eye; dorsal rays 21 to 27; anal 40 to 50; scales about 80 to 90; 
teeth about 17 to 23 above and 16 to 18 on lower jaw. 
4a. Depth 61% to 7 times in standard length; head 414; the greatest 
depth is contained 2% times in distance from anus to base of caudal 
fin; and 144 times in distance from insertion of pelvics to origin 
Offa a fin eee ee Mormyrops breviceps Steindachner 
4b. Depth 5%; head 334; depth 2°45 times in distance from anus to base 
of caudal fin; depth is equal to the distance from pelvic insertion to. 
BNAIKOW Spa ke at Sa a ee Mormyrops deliciosus (Leach) 
36. Mouth inferior; the snout rounded and extending in front of upper 
lip; base of dorsal fin contained 1144 to 1144 times in base of anal fin; 
both nostrils close together and very close to front margin of eye; 
dorsal rays 24 to 28; anal 30 to 84; pectoral 9; depth about 3 in stand- 
ard length; teeth 12 to 14 on upper jaw and 21 to 24 on lower jaw; 
11 or 12 scales around caudal peduncle; 387 or 38 scales in lateral line 
but 54 or 55 rows crossing body above lateral line from gill opening 
to base of caudal fin (anterior 24 of base of anal fin on males 
concave and somewhat swollen______ Petrocephalus simus (Sauvage) 
2b. Teeth fewer than 10 in both jaws and uniserial; posterior nostril an eye’s 
diameter in front of eye. 
5a. Depth 8 to 11 times in standard length; mouth somewhat inferior; base 
of dorsal fin a little longer than anal fin base, the latter contained about 
1.1 to 1.2 times in dorsal fin base; dorsal rays usually 40 to 45; anal 
40 to 44; pectoral 9; scales usually 130 to 185; teeth 5 or 6 in upper 
jaw and 6 in lower jaw; eye small, contained about 10 times in head. 
Isichthys henryi Gill 
50. Greatest depth 3 to 6 times in standard length; mouth terminal or 
subinferior ; base of dorsal fin shorter than anal fin base. 
6a. Mouth a little inferior (subinferior) in position and below level of eye; 
dorsal fin base contained 114 times in anal fin base; depth 4% to 6 
times in standard length, and head 4% to 614 times; dorsal rays 15 
to 18; anal usually 26 to 28; pectoral 9; scales about 57 to 60; 12 
scales around caudal peduncle; pelvic fins a little closer to pectoral 
base thanvanal origina. 2. a ee Mareusenius brachyistius Gill 
