DISTKIBUTION OF FEESHWATEK FISHES. 217 



althougli more numerous, showing no great variety of struc- 

 ture, all belonging to the same group {Amiurina). Towards 

 the south their progress was stiU slower, Tasmania, New 

 Zealand, and Patagonia being without representatives, whilst 

 the streams of the Andes of Chili are inhabited by a few 

 dwarfed forms identical with such 'as are characteristic of 

 similar localities in the more northern and warmer parts of 

 the South American continent. 



After these preliminary remarks we propose the following 

 division of the fauna of Freshwater fishes : — 



I. The Noetheen Zone. — Characterised by Acipenseridte. 



Few Siluridaj. Numerous Cyprinidee. Salmonidae, 

 Esocidse. 



1. Uuropo-Asiatic or Falcearctic Region. — Characterised 



by absence of osseous Ganoidei ; Cobitidse and 

 Barbus numerous. 



2. North American Begion. — Characterised by osseous 



Ganoidei, Amiurina, and Catostomina ; but no Cobi- 

 tidse or Barbus. 



II. The Equatoeial Zone. — Characterised by the develop- 



ment of Siluridse. 



A. Cyprinmd Division. — Characterised by presence of 

 Cyprinidffi and Labyrinthici. 



1. Indian Begion. — Characterised by [absence of 



Dipnoi^] Ophiocephahdse, MastacembeMse. 

 Cobitidse numerous. 



2. African Begion. — Characterised by presence 



of Dipnoi and Polypteridse. Chromides and 

 Characinidse numerous. Mormyridee. Cobi- 

 tidse absent. 



1 Will probably be found. 



