requent ponds are usually capable of bearing a very long
deprivation of water. Indeed, our evolutionists generally hold that land
animals have in every case sprung from pond animals which have gradually
adapted themselves to do without water altogether. Life, according to
this theory, began in the ocean, spread up the estuaries into the
greater rivers, thence extended to the brooks and lakes, and finally
migrated to the ponds, puddles, swamps and marshes, whence it took at
last, by tentative degrees, to the solid shore, the plains, and the
mountains. Certainly the tenacity of life shown by pond animals is very
remarkable. Our own English carp bury themselves deeply in the mud in
winter, and there remain in a dormant condition many months entirely
without food. During this long hibernating period, they can be preserved
alive for a considerable time out of water, especially if their gills
are, from time to time, slightly moistened. They may then be sent to any
address by parcels post, packed in wet moss, without serious damage to
their constitution; though, according to Dr. Guenther, these dissipated
products of civilisation prefer to have a piece of bread steeped in
brandy put into their mouths to sustain them beforehand. In Holland,
where the carp are not so sophisticated, they are often kept the whole
winter through, hung up in a net to keep them from freezing. At first
they require to be slightly wetted from time to time, just to
acclimatise them gradually to so dry an existence; but after a while
they adapt themselves cheerfully to their altered circumstances, and
feed on an occasional frugal meal of bread and milk with Christian
resignation.

Of all land-frequenting fish, however, by far the most famous is the
so-called climbing perch of India, which not only walks bodily out of
the water, but even climbs trees by means of special spines, near the
head and tail, so arranged as to stick into the bark and enable it to
wriggle its way up awkwardly, something after the same fashion as the
'looping' of caterpillars. The tree-climber is a small scaly fish,
seldom more than seven inches long; but it has developed a special
breathing apparatus to enable it to keep up the stock of oxygen on its
terrestrial excursions, which may be regarded as to some extent the
exact converse of the means employed by divers to supply themselves with
air under water. Just above the gills, which form of course its natural
hereditary breathing