280 SILUKID^. 



small adipose dorsal fin ; anal fin much elongate. Pectoral fin with an 

 outer spinous ray. Ventral fin with six rays, inserted under the dorsal 

 fin or behind the vertical of the latter. Four pairs of barbels — nasal, 

 maxillary, and two mentals or mandibulars. Nostrils widely separated. 

 Eye large, with free border. Jaws with a band of villiform teeth ; a 

 band of villiform vomero-palatine teeth. Gill-membranes free, deeply 

 notched. Air-bladder large, free. 



49-55 vertebrse (11-15 + 36-39). 9 or 10 branchiostegal rays. 



Nile and Tropical Africa. 



Synopsis of the Species. 



I. Snout projecting more or less beyond border of mouth, 



A. Base of dorsal exactly above base of 



ventrals ; maxillary barbel longer 

 than outer mandibular ; spine of 

 dorsal at least as long as head ; pec- 

 toral longer than head, reaching origin 

 of anal or a little beyond ; anal 52-63. 1. E. congolensisj Leach, p. 281. 



B. Base of dorsal entirely or partly in advance of base of ventrals ; spine 



of dorsal not longer than head ; pectoral not reaching anal. 



1. Maxillary barbel longer than outer mandibular. 

 a. Anal with more than 50 rays. 



Anal 50 ; pectoral spine feebly serrated on 



inner side ; nasal barbel much longer than 



eye .' 2. E. hamjuelensis, Blgr., p. 2^2. 



Anal 54-69 ; pectoral spine strongly serrated 



on inner side ; nasal barbel not longer 



than eye '?>, E. niloticus, Riipp., p. 283. 



Anal 52-53 ; pectoral spine feebly serrated on 



inner side ; nasal barbel not longer than 



eye I. E. grenfeUi, Blgr,, p. 280. 



h. Anal with not more than 50 rays. 

 Anal 46-50 ; pectoral spine moderately serrated 



on inner side 5, 7i. libenensis, Stdr., p. 287. 



Anal 38-45 ; pectoral spine feebly serrated on 



both sides 6. 7:*. debamci, Blgr., p. 288. 



2. Maxillary barbel not longer than outer mandibular ; anal 52-62. 

 Maxillary barbel longer than the nasal ; caudal 



peduncle a little deeper than long . . . I.E. meiUali.'!, Blgr,, p. 2SS. 

 Maxillary and nasal barbels subequal ... 8. E. mandibular^, Gthr., p, 290. 



