510 Transactions. — Miscellaneous. 



2. The great increase in the yearly growth of our trout, compared to 

 that of trout in a wild state at Home, is neither a new nor so very wonderful 

 a variation. It seems to me to be due entirely to new and abundant food, 

 and it may to some extent be to new water, also to the constitution or stock 

 of trout. The same has occurred in Scotland, and with a warning note too 

 to us in New Zealand. Mr. J. A. Harvie Brown, of Dunipace, stocked a 

 loch in the north of Scotland, which had no trout in it at all. In two years 

 they multiplied and attained a weight of 4-J lbs. So soon, however, as the 

 trouts' numbers exceeded the food supply, or in two years, they fell off in 

 condition, colour, etc., and latterly were not worth catching. Like cases 

 have occurred elsewhere at home. 



3. The colour and markings seem to be controlled, to some extent, by 

 the nature of the water and bottom, among trout of equal age and the same 

 sex, and to be partly an individual quality. But, as to food affecting the 

 colours, I cannot at present offer a very decided opinion ; but will mention 

 this — that the Shag Biver trout are all silvery, while those of the Waipahi 

 are mostly dark and golden, the food being the same, but the geologi- 

 cal formation and water very different in these two rivers. I have 

 seen a like variation in colour in two different parts of the same river 

 (the Endrick) in Scotland, with presumably one and the same sort of 

 food. 



4. There does appear to be a considerable difference in the form of the 

 suboperculum between our trout and Yarrell's typical specimen ; but it is 

 not by any means certain that the latter was of the same species. Also, 

 while the form, with our trout, of this bone varies greatly, one or two 

 examples (fig. 2, p. 503), got by me within the last year or two, show a 

 decided tendency to revert to Yarrell's form. On the other hand, his draw- 

 ing of S.fario ausonii, p. 261, vol. i., shows this bone very much as it may 

 be seen in the great majority of our trout ; so that there is hardly any 

 ground for believing that a new form or shape of bone has been induced by 

 a change to the antipodes. 



5. There is no alteration in the number of fin rays of any moment ; but 

 whether the variation in size of the fins is the same as at Home, is a matter 

 which I have scarcely the means of deciding. 



6. The scales appear to be more plentiful than in trout described by Dr. 

 Gimther, but I can only repeat that probably no two observers would find 

 the same number, owing to their disappearance on the outlines of the 

 body. 



7. The vertebra are not practically different in number from those 

 recorded of the progenitors of our trout. 



