4 POLTPTERID^E. 



Tropical seas, entering rivers. Ascends the Zambesi and the Shire 

 and probably other African rivers.— Type in Paris Museum. 

 1, 2. Saws o£ half-grown specimens. Zambesi. Sir J. Kirk (P.). 



3_ jjo-r. Gambia. Sir A. Moloney (P.). 



Subclass TELEOSTOMI. 



Skeleton more or less ossified; membrane bones present; jaws 

 present. Exoskeleton of scales or bony plates. No mixopterygia. 



Order I. CROSSOPTERYGII. 



Paired fins, at least the pectorals, lobate, with an endoskeletal axis 

 fringed with dermal rays. Mandibular arch suspended from the upper 

 segment of the hyoid or hyomandibular arch (hyostylic skull) ; no 

 supraoccipital bone; splenial present. Bulb of aorta muscular, with 

 several rows of valves. 



Suborder I. CLADISTIA. 



Pectoral fin tribasal. Nostrils on upper surface of snout. 



Fam. 1. POLYPTERlDiE. 



Body covered with rhombic bony scales with enamel-like coating. 

 Dorsal fin formed of a series of spines with one or several articulated 

 rays supporting a membrane, forming detached finlets. Head covered 

 with bony plates ; maxillary bone bordering the eye ; a spiracle, covered 

 by a bony valve, on each side of the top of the head. Branchiostegal 

 rays replaced by a pair of large bony plates between the mandibular 

 rami. Young with an external opercular gill. Vent opening far back. 

 Vertebral column ossified, diphycercal. Air-bladder double, with 

 pneumatic duct communicating with the ventral side of the oesophagus. 



Two genera, both African : — 



Ventral fins present 1. Fohjpterus, Geofifr., p. ,5. 



No ventral fins 2. Ca/a»»V/,%«, J. A. Smith, p. 17. 



