and the consequence is, that they are more likely to be affected by severe droughts and great floods—the first killing, and the second washing away the larvæ and aurelias. May-flies thirty years ago were abundant in the upper part of the Teme river in Herefordshire, where it receives the Clun: they are now rarely seen. Most of the rivers of that part of England, as well as of the west, with the exception of those that rise in the still uncultivated parts of Dartmoor and Exmoor, are rapid and unfordable torrents after rain, and in dry summers little more than scanty rills; and Exmoor and Dartmoor, almost the only considerable remains of those moist, spongy, or peaty soils, which once covered the greatest part of the high lands of England, are becoming cultivated, and their sources will gradually gain the same character as those of our midland and highly-improved counties. I cannot give you an idea of the effects of peat mosses and grassy marshes on the water thrown down from the atmosphere, better, than by comparing their effects to those of roofs of houses of thatched straw, as contrasted with roofs of slate, on a shower of rain. The slate begins to drop immediately, and sends down what it receives in a rapid torrent, and is dry soon after the shower is over. From the sponge-like roof of thatch, on the contrary, it is long before the water drops; but it continues dropping and wet for hours after the shower is over and the slate dry. POIET.—You spoke just now of the gillaroo trout, as belonging only to Ireland. I can, however, hardly bring myself to believe, that such a fish is not to be found elsewhere. For lakes with shell-fish and char are common in various parts of Europe, and as the gillaroo trout is congenerous, it ought to exist both in Scotland and the Alpine countries. HAL.—It is not possible from analogies of this kind to draw certain inferences. Subterraneous cavities and subterranean waters are common in various countries, yet the Proteus Anguinus is only found in two places in Carniola—at Adelsburg and Sittich. As I mentioned before, I have never yet met with a gillaroo trout except in Ireland. It is true, it is only lately that I have had my attention directed to this subject, and other fishermen or naturalists may be more fortunate. POIET.—Have you ever observed any other varieties of the trout kind, which may be considered as, like the gillaroo, forming a distinct species? HAL.—I think the par, samlet, or brandling, common to most of our rivers, which communicate with the sea, has a claim to be considered a distinct species; yet the history of this fish is so obscure, and so little understood, that, perhaps, I ought not to venture to give an account of it. But in doing so, you will consider me as rather asking for new information, than as attempting a satisfactory view of this little animal.