Arruur.—On the Brown Trout introduced into Otago. 473 
Growth, 
It is of the first importanco, at this stage, to be sure of the real species 
of trout which has been introduced into Otago—the progeny of the original 
lot got for us in Tasmania by Mr. G. P. Clifford, in 1868. Now, Mr. 
Clifford has told me there could be no crossing with S. salar or S. trutta at 
the breeding ponds on the Plenty, in Tasmania, as the trout there were 
carefully kept separate, and in ponds by themselves. So far, good; and as 
I stated in my previous paper, the original ova from England were taken 
from three rivers, the Weycombe, Buckinghamshire, and the Wey, by Mr. 
Francis Francis; and from the Itchen, by Mr. Frank Buckland. The 
Salmon Commissioners of Tasmania, however, so far as 1 could find out, 
have not placed on record the precautions taken, if any, to keep the lots 
separate in the hatching-boxes, or to say what proportion of each were 
reared and produced ova. All I have been able to learn is that many ova 
died, and that it is impossible to determine which English river or rivers 
may be represented by the progeny. However, taking Dr. Günther's 
arrangement of species as my guide, it determines the trout from any of the 
above-named rivers to be S. fario ausonii, or the southern form, which I 
take to be the same as the Thames trout. It is capable of growing to a 
large size in its native streams, or may be called a large-framed trout, and 
is believed by good authorities to drop down into brackish water sometimes, 
or even as far as the sea itself. While it may be admitted readily that this 
trout does sometimes migrate in this manner, I must remark that I have 
never seen any absolute demonstration of the fact adduced by any author. 
But I shall have occasion again to offer my own observations on this P 
and so shall leave it alone now. 
The period of hatching at our Opoho hatchery may be seen from the 
following examples :— 
Year and Locality Trout Ova Last Ovum Time of Hatching | Temp. of Water. 
got Hatched. in days. Fah. 
1868 Ponds at Plenty, Tasmania October 30th About 70 
18 5 ” ” ” 3? 14th ” 70 
1878 Otago Rivers "B e ae » 1178 499—592? 
1879 RR oo Bard: 78—88 41°—504° 
1880 ý sù ES » 80th 80—95 40°— 57° 
1881 h Qus „ 00h 64—75—77 41°—53° 
1882 ” eres ^» 80th 70—80 39°—50° 
The Tasmanian ova may properly be omitted in determining the ordinary 
time taken for hatching, as they were subjected to unusual vicissitudes 
before reaching Otago. The mean time of the other lots taken from trout 
in Otago waters is 78 days, or, leaving out the manifestly abnormal dura- 
tions of 64 and 95 days, we get a range of 70 to 88 days, or, on an average, 
