78 
MR. F. DAY ON THE LOCH-LEVEN TROUT. 
this is certainly sometimes the case, but such a character is not 
persistent. In the form of the body there is no difference percep- 
tible in those fish reared in Gloucestershire, as I shall presently 
show, or at Mr. Andrews’s establishment at Guildford, from eggs 
obtained from Howietoun, and young of brook-trout raised from 
local brook-trout eggs. As this is the case in fish reared from Loch- 
Leven eggs it is evident that their form ultimately depends upon 
local circumstances or conditions ; for if they are removed to an- 
other locality where the conditions are different, the brook-trout 
form is at once seen. The same observations apply to the length 
of the head, which in some well-fed examples, and, in fact, gene- 
rally in the young raised at Howietoun, is a little shorter in pro- 
portion to the length of the body than usual in the brook-trout, 
but this changes on their being transferred to a new home. 
As to the length of the rays of the caudal fin * being longer 
than in the brook-trout, I have been unable to find that such is 
the case, either in specimens from Howietoun, from Loch Leven, 
or in those in the British Museum, as they seem to be absolutely 
identical in the two forms. In a skeleton of a female 20 inches 
long, I find the middle caudal ray is 2‘1 inches in length, and the 
longest outer ray 29 inches ; but were Dr. Gunther’s figures, as 
noted below, to be applicable to these fish, the outer ray should 
be 4T inches in length. Such proportions I have never seen in any 
of the thousands of these fish I have observed at Howietoun or 
elsewhere, not omitting those in the British Museum. Specimens 
having the angle of this fin pointed would appear to be young 
fish, often males, kept, as at Howietoun, where they are not dis- 
turbed ; but in the old fishes this fin is invariably rounded at its 
posterior extremity. 
The statement that the pectoral fin is pointed is partially cor- 
rect in small specimens, as it also is in small brook-trout, but in 
old and well-preserved examples it is as rounded as in other 
races of freshwater trout f. 
As to the male having no knob on the lower jaw, that likewise 
* “ In specimens 13 inches long, the middle caudal rays are not quite half as 
long as the outer ones, and in older ones they are half as long.” (Giintker.) 
In a specimen 13^ inches long the middle caudal ray was 1 inch in length and 
the outer or longest one 1|. 
t In order to demonstrate this, dried examples of the pectoral fin taken from 
fishes of this race at various ages were shown at the Meeting when the paper 
was read. 
