The migrations of the sole, as of so many flat-fish, may in
all probability be regarded as being restricted to a general
movement to deeper water during the extreme cold of winter,
and possibly also a food-migration into the shallows in summer
time. This would not, however, include the spawning fish.
Professor McIntosh describes the egg of the sole as hardy
and the larva as extremely active, and he attributes the strange
fashion in which the latter rushes about in its tank to the needs
of respiration, for he has observed that it darts about open-
mouthed. This, he rightly points out, need not be the habit
of the little sole in the open sea, but is simply a habit acquired
in confinement and necessitated by the absence of invigorating
currents in the tank. ‘The breast-fins, he says, vibrate like
those of the sea-horse, and there is also rapid movement in
the tail.
As a single instance of what may be done by transplanting
sea-fish from characteristic localities to those in which they
were either rare or altogether unknown,t it may be mentioned


* See an interesting account of this by Mr. Butler in the Journ.
Mar. Biolog. Assoc. September, 1895, p. 3.
tT See also Mr. R. B. Marston’s remarks in Chapter XVI.
THE FLAT-FISHES 237


that about ten years ago some five hundred soles were con-
veyed from English waters to St. Andrews Bay by Professor
McIntosh, under the auspices of the Scotch Fishery Board,
and the Professor is able to say that both the adult sole and
the egg have been more frequently encountered on that part
of the Scotch coast since this experiment was made.
