Page:The Zoologist, 4th series, vol 2 (1898).djvu/477

Rh "innumerable rises." "On closer inspection these will prove to be fish taking what I believe are called the nymphæ of the Duns or Mayflies just before they reach the surface, there to hatch out."

Col. Custance deals somewhat exhaustively with Troutbreeding. "The three principal breeds of freshwater Trout raised by the British fish-culturist are the English Brook Trout (Salmo fario), the Loch Leven Trout (S. levenensis), and last, but not least, the Rainbow Trout (S. irideus). The first is the one used for general stocking purposes in this country; S. levenensis, although a lake Trout, will also thrive in rivers where there is a considerable depth of water; but Col. Custance gives his vote for the Rainbow Trout, which originally came from America. He describes it as almost satisfying "the Trout-breeder's ideal of perfection." "A splendid surface feeder, he will readily accommodate himself to new water, and will, under favourable conditions, grow with extraordinary rapidity and to a great size."

S. irideus has a common frailty of the Salmonidæ in a propensity to cannibalism, but he is considered to have less of that quality than S. fario, but this is owing to the Rainbow Trout having the smaller mouth.

We may say that the authors of this little volume are anglers among naturalists, and naturalists among anglers.