468 Transactions.— Miscellaneous. 
a difficult problem to settle satisfactorily. It thus appears that the need for 
careful revision of those distinctions is recognized by these two eminent 
authorities on ichthyology. 
My subject naturally suggests for its elucidation such considerations and 
facts as explain the distribution, growth, habits, and structure of our trout. 
Besides many trout which I have handled and observed as to external mark- 
ings during the past five years, the evidence I shall give (particularly on 
their structure) is more strictly confined to my examination of seventy-five 
specimens, taken from nineteen different rivers and waters, including one 
interesting trout from a Canterbury stream. The fish were of both sexes, 
and varied in weight from 41b. to 17 lbs. In the appendix to this paper I 
shall give some particulars of each fish as noted on examination of a certain 
number. 
I.— Distribution. 
Absolute precision in ascertaining the facts in the life-history of our 
trout in their wild state, so as to deduce from these the general laws to 
which they are subject, would necessitate so much positive labour, inspired 
by enthusiasm, that I despair of its attainment in New Zealand. Neither 
am I aware that such has been attempted in older countries, as England, 
Germany, and North America, where the social advantages are more favour- 
able towards supplying the necessary leisure and means. For these obser- 
vations include such as refer to the geological formation surrounding a river or 
lake, the chemical constitution of the water, the supply and variety of food, and 
the meteorological conditions of the atmosphere, with the marking, recapture, and 
examination of the trout, also their natural enemies. Many different rivers also 
would require to be included, owing to their varying characters, and the 
observations should extend over many years. Many may think this pro- 
gramme of work superfluous, and may here ask, have we not the experience 
of aquaria and of fish-hatching establishments to guide us? Quite so, but 
it must be remembered that the habits of fish so situated are of fish in con- 
finement, where it is impossible to afford them the advantages of nature, so 
that their habits must, to a considerable extent, be forced and unnatural, 
and therefore misleading. Such being the position of matters, the best that 
one can do at present is to lay under contribution such information as may 
be at command, imperfect though it may be. What then are the circum- 
stances of our rivers and lakes, and what the effects so far on introduced 
trout ? eek 
Geological formation.—Nearly all our rivers originate among mountains 
of gneiss and conglomerate, which drain the country from the Waitaki River 
on the northern boundary of Otago, southwards to a line drawn from Bal- 
clutha on the Clutha River, to the Mataura River passing over Popotunoa 
