1882. | BETWEEN SALMON AND TROUT. 753 
of the longest outer one. The maxilla extends posteriorly to beneath 
the posterior third of the eye. The preopercle has a distinctly oblique 
lower limb, which in this example is less strongly marked than in 
No. 2, while merely a simple curve exists in Nos. 3 and 4. 
The central caudal ray is half the length of the longest outer one 
in examples 1 and 2, but two thirds in Nos. 3and 4. Respecting the 
cxcal appendages, Nos. 3 and 4 were first immersed in a weak solution 
of chromic acid, which has hardened them, facilitating their being 
counted. No. 3 contained 78, and No. 4 had 61; the other two 
were not examined. If hybrids between the Lochleven Trout and 
a male Salmon show such variations, it demonstrates the inconstancy 
of the number of these appendages. We took two Lochleven Trout, 
each similar in appearance, and about 8 inches in length, which 
had been bred at Howietoun from eggs and milt of fish inhabiting 
the stock-ponds, and were consequently one generation removed from 
Lochleven parentage ; in one they were short and 40 in number, in 
the other rather long and 67. (The preparations are on the table.) 
Respecting the scales, from 120 to 121 rows descend from the 
back to the lateral line. In Nos, 1, 3, and 4 there are 13 passing 
downwards and forwards from the hind edge of the base of the 
adipose dorsal fin to the lateral line, while in No. 2 there are 12. 
Colours. These are nearly identical in all four ; from 12 to 13 lateral 
parr bands pass down the sides, which are also more or less closely 
sprinkled with small black spots and some few red ones ; there are also 
black spots on the gill-covers and on the upper surface of the head. 
A very remarkable feature common to all is that the dorsal fin has 
its front upper edge white, with a black intramarginal band, and 
from 11 to 13 black spots on or between the rays. Attention may 
here be directed to no white upper edging existing on the dorsal fin 
in any of the Lochleven variety of Trout at Howietoun, such a mode 
of colour being restricted to the burn-trout variety at that estab- 
lishment ; and this forms another link in the chain of facts that these 
two forms are merely varieties of one species. 
I wish here to record some experiments commenced on November 
15th by Sir J. Gibson-Maitland, while I and others were present. 
About 3000 ova were obtained from Lochleven Trout, and fer- 
tilized with the milt of the American Charr, Salmo fontinalis. They 
were placed in hatching-box No. 108. 
About 8000 ova of the American Charr were milted from Loch- 
leven Trout, and placed in hatching-box No. 104. 
About 9000 ova of the American Charr were fertilized with the 
milt of a Scotch Charr which has been termed Salmo struanensis, 
and placed in hatching-box No. 115. 
In Austria, observes Peyrer, the Charr (Salmo salvelinus) is crossed 
with the Trout ; and the young excel the pure breed in many respects. 
Whether this is partly due to their being sterile, and consequently 
not going out of season subsequently to the breeding-season, is not 
mentioned. The life-history of these true hybrids cannot but be 
interesting ; and such in due time will doubtless be forthcoming 
from Howietoun. 
50* 
