Even admitting the soundness of his theory, and the probability that, under favourable circumstances, the spawn in the tanks might be preserved during the dry season so as to contribute to the perpetuation of their breed, the fact is no longer doubtful, that adult fish in Ceylon, like some of those that inhabit similar waters both in the New and Old World, have been endowed by the Creator with the singular faculty of providing against the periodical droughts either by journeying overland in search of still unexhausted water, or, on its utter disappearance, by burying themselves in the mud to await the return of the rains. It is an illustration of the eagerness with which, after the expedition of Alexander the Great, particulars connected with the natural history of India were sought for and arranged by the Greeks, that in the works both of ARISTOTLE and THEOPHRASTUS facts are recorded of the fishes in the Indian rivers migrating in search of water, of their burying themselves in the mud on its failure, of their being dug out thence alive during the dry season, and of their spontaneous reappearance on the return of the rains. The earliest notice is in ARISTOTLE'S treatise _De Respiratione_[1], where he mentions the strange discovery of living fish found beneath the surface of the soil, "[Greek: tôn ichthyôn oi polloi zôsin en tê gê, akinêtizontes mentoi, kai euriskontai oryttomenoi?]" and in his History of Animals he conjectures that in ponds periodically dried the ova of the fish so buried become vivified at the change of the season.[2] HERODOTUS had previously hazarded a similar theory to account for the sudden appearance of fry in the Egyptian marshes on the rising of the Nile; but the cases are not parallel. THEOPHRASTUS, the friend and pupil of Aristotle, gave importance to the subject by devoting to it his essay [Greek: Peri tês tôn ichthyôn en zêrô diamonês], _De Piscibus in sicco degentibus_. In this, after adverting to the fish called _exocoetus_, from its habit of going on shore to sleep, "[Greek: apo tês koitês,]" he instances the small fish ([Greek: ichthydia]), that leave the rivers of India to wander like frogs on the land; and likewise a species found near Babylon, which, when the Euphrates runs low, leave the dry channels in search of food, "moving themselves along by means of their fins and tail." He proceeds to state that at Heraclea Pontica there are places in which fish are dug out of the earth, "[Greek: oryktoi tôn ichthyôn]," and he accounts for their being found under such circumstances by the subsidence of the rivers, "when the water being evaporated the fish gradually descend beneath the soil in search of moisture; and the surface becoming hard they are preserved in the damp clay below it, in a state of torpor, but are capable of vigorous movements when disturbed." "In, this manner, too," adds Theophrastus, "the buried fish propagate, leaving behind them their spawn, which becomes vivified on the return of