ontribute 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.

Eels kept in a garden, when August arrived (the period at which instinct
impels them to go to the sea to spawn) were in the habit of leaving the
pond and were invariably found moving eastward _in the direction of the
sea_.--YARRELL, vol. ii. p. 384. Anglers observe that fish newly caught,
when placed out of sight of water, always struggle towards it to
escape.]

Pallegoix in his account of Siam, enumerates three species of fishes
which leave the tanks and channels and traverse the damp grass[1]