CATALOGUE 



OF 



AFRICAN FRESH-WATER FISHES. 



Subclass SELACHII. 



Skeleton cartilaginous, no membrane l)ones ; jaws present. Exo- 

 skeleton of dermal denticles, structurally identical with teeth. Males 

 with paired intromittent organs (mixopterygia) attached to the ventral 

 fins. 



Order I. PLAGIOSTOMI. 



Several (5-7) gill-clefts opening directly to the exterior. Pterygo- 

 quadrate distinct from the cranium. 



Suborder I. P L E U R O T R E M I. 



Gill-openings lateral, tlie last in front of or above the base of the 

 pectoral fin. 



Fam. 1. CARCHARIID.E. 



Mouth inferior. Eye with a nictitating membrane; spiracles small 

 or absent; 5 gill-openings, one or two above the base of the pectoral fin. 

 Two dorsal fins and one anal ; caudal fin usually of the Avell-marked 

 heterocercal type. 



VOL. 1. B 



