317 
because such shells require a strong embryo in order to hatch, 
which is obtained by augmenting the water supply during the 
eyed period. 
Eggs of Salmonide differ not only with the age of the fish, 
but from various causes, and it is-now necessary to show why I 
believe that the offspring from large eggs are superior to such 
as are reared from small ones, and why fish culturists should be 
careful to obtain their stock from the best sources, unless the 
water in which they are going to be placed is deficient in 
amount or in food when the source from whence the breed is 
obtained is of very little, if any, consequence. Two batches of 
Loch Leven trout were spawned on November 2, 1882, at 
Howietoun, the parents of one lot having been hatched in 1875, 
and of the other in 1876; the eggs were similarly treated, and 
the young came out during January and February, 1883. At 
Craigend are two ponds, which have been constructed for the 
reception of young fish, each 100ft. long and of the same 
width ; one is nearly on a level with the other, and the iden- 
tical stream passes through both. Into these two ponds the 
two lots of fry were turned, those from the older parents (1875), 
or seven-year-old parents, having the lower pond; those from 
the younger or six-year-old fish having the upper pond, while 
they were fed and otherwise similarly treated. At the end of 
November, 1883, those in the lower pond were about one-fourth 
larger than those in the upper pond, and it seemed as if the 
produce of the older parents or larger eggs were decidedly 
superior to those from the younger parents, or smaller eggs. 
In 1884 a second experiment was tried in the same two 
ponds, which were stocked with young Loch Leven trout, bred 
from parents of the same age, spawned the same day and 
hatched in the same room. I saw these fish both in August 
and also in November, but no difference in size or appearance 
was perceptible between them. It would, consequently, seem 
that the larger eggs produced from older parents produce 
fry which grow faster than do those from the smaller eggs 
furnished by younger parents. 
In the evidence taken before the Salmon Commission of 
1824, Mr Lirrie observed that “the Shannon fish are very 
