Relations of the New-Zealand Fauna. 87 



dence as to the former distribution of land than those inhabit- 

 ing the sea. Of these, New Zealand possesses fifteen species 

 belonging to seven genera, of which six species, or 40 per 

 cent., and one genus are found nowhere else. That the per- 

 centage of the endemic freshwater fish should be nearly the 

 same as that of the marine fish is a remarkable and unex- 

 pected result ; for the number of species of marine fish inha- 

 biting New Zealand and found also in other countries de- 

 pends partly on permanency of specific characters since New 

 Zealand was isolated, and partly on the power possessed by 

 fishes of migrating to us from other countries, while among 

 the freshwater fish the proportion depends entirely on perma- 

 nency of specific characters ; consequently this permanency of 

 specific characters must be greater in freshwater than in salt- 

 water fish ; and this is the more remarkable as our freshwater 

 fish are far more variable, especially Galaxias attenaatus and 

 Eleotris gobioides^ than the marine ; and Galaxias attenuatus^ 

 being found both in South America and in Tasmania, must 

 have had a longer specific existence than any of the others. 

 It is therefore evident that a great amount of variability is not 

 inconsistent witli great specific longevity under certain con- 

 ditions. The conditions in this case are, I believe, the absence 

 of any large rapacious fish preying on the smaller variable 

 ones, and thus tending to fix those varieties which are best 

 adapted to elude the observation of the enemy. These condi- 

 tions will soon no longer exist in our rivers, on account of the 

 introduction of the trout ; and I should like to draw attention 

 to tlie fact that descriptions and figures of all the varieties of 

 fish occurring now in one or more of our rivers would be a 

 most valuable contribution to science as material for future 

 naturalists. 



Of our freshwater fisli found beyond New Zealand, Retro- 

 innna Richardsoni is found in the Chatham Islands, Galaxias 

 fasciatus in both the Chatham and Auckland Islands, Galaxias 

 attenuatus in the Chatham Islands, Tasmania, Patagonia, and 

 South America, Galaxias olidus in Australia, Anguilla auck- 

 landil in the Auckland Islands, Anguillu australis in the 

 Auckland Islands, Tasmania, and Timor, Anguilla latirostris 

 in the Chatham Islands, Europe, Egypt, China, and the West 

 Indies, Geotria australis in Australia, and Geotria chilensis 

 in Western Australia and Chile. Thus four of our freshwater 

 fish are found in the Chatham Islands and three in the Auck- 

 land Islands, which are all the freshwater fish known to in- 

 habit those places ; three are found in Australia, two in Tasma- 

 nia, two in South America, one in the island of Timor, and one is 

 spread from China to Europe and the West Indies. The Aus- 



