242 Transactions.— Zoology. 
The fresh-water fish naturally supply more important evidence as to the 
former distribution of land than those inhabiting 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 percentage 
of the endemic fresh-water fish should be nearly the same as that of the 
marine fish is a remarkable and unexpected result, for the number of species 
of marine fish inhabiting New Zealand and found also in other countries 
depends 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 fresh-water fish the proportion depends 
entirely on permanency of specific characters ; consequently, this permanency 
of specific characters must be greater in fresh-water than in salt-water fish, 
and this is the more remarkable as our fresh-water fish are far more variable, 
especially Galaxias attenuatus and Eleotris gobioides, than the marine, and 
Galaxias attenuatus being found both in South America and 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 with great 
specific longevity under certain conditions. 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 conditions will soon no longer exist in 
our rivers on account of the introduction of the trout, and I should like to 
draw attention to the 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 fresh-water fish found beyond New Zealand, Retropinna 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 
aucklandii in the Auckland Islands; Anguilla 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 fresh- 
water fish are found in the Chatham Islands, and three in the Auckland 
Islands, which are all the fresh-water fish known to inhabit those places ; three 
are found in Australia, two in Tasmania, two in South America, one in the 
Island of Timor, and one is spread from China to Europe and the West Indies, 
The Australian grayling also (Prototroctes marena), although a distinct 
Species, much resembles our own (P. oxyrhynchus); and another closely 
related genus (Haplochiton) is found in South Ameriéa. 
genus Lleotris is widely spread in tropical countries. Its head quarters 
