In Finnland the water-god was Ahti, or Ahto, on the etymology of which name the Finnish language throws no light: Castrén, however, compares it with the Sanskrit ahis, lake, and the Old Norse ahi, the world-surrounding serpent, that is the sea, (ægir, Lat. æquor.)  Like other Finnish deities, he is represented as an aged venerable man; but he wears a robe of foam, and is bearded with grass like a Roman river-god.  This Water-host, or Wave-king, as he is called, dwells with his stern and aged spouse, Vellámo, at the bottom of the sea, in a chasm called Salmon-rock or Fish-court, where his palace Ahtola is built.  He possesses (besides the fishes, his peculium) an untold treasure, which he has acquired in consequence of fragments of the mystical, luck-bringing Sampo having been sunk in the sea by the Hostess of Pohjola.  Although greedy for the goods of others, and seldom returning any portion of what falls into his hands, he is by no means incapable of generosity.  He receives the drowned with hearty kindness, and once, when a herd-boy was chipping wood on a river-bank, and his knife fell into the water, Ahti (like the god in the Æsopean fable of Mercury and the Woodman)—

"Moved by his weeping over the mischance that had befallen him, came swimming to shore, dived down to the bed of the river, and brought up from thence a golden knife.  Full of honest innocence, the boy assured the god that that knife did not belong to him.  Then Ahti dived down a second time, and brought up a silver knife, and when the boy refused to take this also, Ahti betook himself a third time to the river-bed and brought from thence the right knife, which the boy gladly recognized as his own.  To reward the child for his upright dealing, Ahti gave him the three knives."

(Eclectic Magazine of Foreign Literature, Bidwell, Nov. 1857).