458 GEOGRAPHICAL ZOOLOGY. [PART iv. 



SUB-CLASS II. DIPNOI. 



FAMILY 92. SIRENOIDEI. (3 Genera, 3 Species.) 



" Eel-shaped fresh-water fishes, covered /with cycloid scales ; 

 the vertical fins forming a continuous border to the compressed 

 tapering tail." 



DISTRIBUTION. Eivers of Tropical Africa, South America, and 

 Australia. 



The genera are : Protopterus (1 sp.), Tropical Africa ; Lepido- 

 siren (1 sp.), Amazon Valley ; Ceratodus (1 sp.), Queensland. 



SUB-CLASS III. GANOIDEI. 



Order LHOLOSTEL 

 " Body covered with scales." 



FAMILY 93. AMIIDJE. (1 Genus, 1 Species.) 



" A fresh-water fish, with cycloid scales and a long soft dorsal 

 fin." 



DISTRIBUTION. United States. 



FAMILY 94 POLYPTEEID^E. (2 Genera, 2 Species.) 

 " Fresh- water fishes, with ganoid scales and dorsal spines." 

 DISTRIBUTION. Central and Western Africa. 



The genera are : 



Polypterus (1 sp.), the Nile and rivers of West Africa; Cctla- 

 moichthys (1 sp.), Old Calabar. 



