year, unlike those of Europe, they never hybernate. A similar observation applies to bats, which are dormant during a northern winter when insects are rare, but never become torpid in any part of the tropics. The bear, in like manner, is nowhere deprived of its activity except when the rigour of severe frost cuts off its access to its accustomed food. On the other hand, the tortoise, which in Venezuela immerses itself in indurated mud during the hot months shows no tendency to torpor in Ceylon, where its food is permanent; and yet it is subject to hybernation when carried to the colder regions of Europe. [Footnote 1: _Annals of Natural History_, 1860. See Dr. BAIRD'S _Account of Helix desertorum; Excelsior,_ &c., ch. i. p. 345.] [Footnote 2: Colonel SKYES has described in the _Entomological Trans._ the operations of an ant in India which lays up a store of hay against the rainy season.] To the fish in the detached tanks and pools when the heat, by exhausting the water, deprives them at once of motion and sustenance, the practical effect must be the same as when the frost of a northern winter encases them in ice. Nor is it difficult to believe that they can successfully undergo the one crisis when we know beyond question that they may survive the other.[1] [Footnote 1: YARRELL, vol. i. p. 364, quotes the authority of Dr. J. Hunter in his _Animal oeconomy_, that fish, "after being frozen still retain so much of life as when thawed to resume their vital actions;" and in-the same volume (_Introd_. vol. i. p. xvii.) he relates from JESSE'S _Gleanings in Natural History_, the story of a gold fish (_Cyprinus auratus_), which, together with the a marble basin, was frozen into one solid lump of ice, yet, on the water being thawed, the fish became as lively as usual. Dr. RICHARDSON in the third vol of his _Fauna Borealis Americana_, says the grey sucking carp, found in the fur countries of North America, may be frozen and thawed again without being killed in the process.] _Hot-water Fishes_.--Another incident is striking in connection with the fresh-water fishes of Ceylon. I have described elsewhere the hot springs of Kannea[1], in the vicinity of Trincomalie, the water in which flows at a temperature varying at different seasons from 85° to 115°. In the stream formed by these wells M. Reynaud found and forwarded to Cuvier two fishes which he took from the water at a time when his thermometer indicated a temperature of 37° Reaumur, equal to 115° of Fahrenheit. The one was an Apogon, the other an Ambassis, and to each, from the heat of its habitat, he assigned the specific name of "thermalis."[2] [Footnote 1: See SIR J. EMERSON TENNET's _Ceylon_, &c., vol. ii. p. 496.]