But supposing it possible to carry the spawn sufficiently deep, and to deposit it safely in the mud below, which is still damp, whence it could be liberated on the return of the rains, a considerable interval would still be necessary after the replenishing of the ponds with water to admit of vivification and growth. But so far from this interval being allowed to elapse, the rains have no sooner ceased than the fishing of the natives commences, and those captured in wicker cages are mature and full grown instead of being "small fish" or fry, as affirmed by Mr. Yarrell.
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 inhabitants, 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.
_Travelling Fishes._--It was well known to the Greeks that certain fishes of India possessed the power of leaving the rivers and returning to them again after long migrations[1] on dry land, and modern observation has fully confirmed their statements. The fish leave the pools and nullahs in the dry season, and led by an instinct as yet unexplained, shape their course through the grass towards the nearest pool of water. A similar phenomenon is observable in countries similarly circumstanced. The Doras of Guiana[2] have been seen travelling over land during the dry season in search of their natural element[3], in such droves that the negroes have filled baskets with them during these terrestrial excursions.
[Footnote 1: I have collected into a note, which will be found in the appendix to this chapter, the opinions entertained by the Greeks and Romans upon this habit of the fresh-water fishes of India. See note B.]
[Footnote 2: _D. Hancockii_, Cuv. et Val.]
[Footnote 3: Sir R. Schomburgk's _Fishes of Guiana_, vol. i. pp. 113, 151, 160. Another migratory fish was found by Bose very numerous in the fresh waters of Carolina and in ponds liable to become dry in summer. When captured and placed on the ground, "they _always directed themselves towards the nearest water, which they could not possibly see_, and which they must have discovered by some internal index." They belong to the genus _Hydrargyra_, and are called Swampines.-- KIBBY, _Bridgewater Treatise_, vol i. p. 143.