A CONTRIBUTION TO THE ICHTHYOLOGY 167 



Among these fishes, some different groups with regard to 

 their range and habitats can be traced. 



To one group, belong the species characterized by a very wide 

 range, some of them being chiefly marine in their occurence and from 

 the sea entering the estuaries and rivers, while others are more 

 typical brack-water fishes, which extend their range up the rivers. 

 Such species are here represented by Carcharis gangeticus, 

 Megalops cyprinoides, Toxotes chalcareus, Lates calcarifer, 

 JPeriophthalmus koelreuteri, and Gobius giuris. 



To a second group, I refer those purely or chiefly fresh- 

 water fishes, which have been stated only from waters of the 

 Australian continent. Some of these are rather widely distibuted 

 in Australia, as Arius australis, Terapon percoides and Tera- 

 pon unicolor, while the others, Chatoessus erehi and Glossa- 

 mia aprion evidently have a more restricted northern range. 



The third group comprises species, which occur in Australia 

 and in New Guinea as well. To these is to be referred Melano- 

 taenia nigrans, which according to Regan's researches also 

 occurs in the Aru Islands. Other species belonging to this group 

 are Arius stirlingi, Belone krefftii, Eleotris mogurnda, and 

 Pogoneleotris inicrops. The first three species have a decided 

 northern distribution in Australia, P. microps is in this paper 

 for the first time stated from this continent. 



Summarizing, the fresh water fish- fauna of Arnhem Land 

 as represented in the present collection: 



1, seems to have several endemic forms, related to other Au- 

 stralian or to New Guinean species, 



2, partly is composed of species of a wide but exclusively 

 Australian habitat, 



3, partly of species also occurring in New Guinea and for 

 the most part in northern Australia as well (the occurrence 

 of a species of the genus Rhomhosoma in Arnhem Land 

 confirms this affinity with the fauna of New Guniea), and 



