LONDON (AP) _ An American collector paid a record $755,000 Wednesday for a lost painting of Venice by Antonio Canaletto that was found in a home in Glasgow, Sotheby's auctioneers said.

The American, who bid by telephone, was not identified, but his Sotheby's said the bid was a record sale price of a Canaletto painting. The previous top price for a Canaletto was $620,000 at Christie's in New York in January 1984.

Canaletto, a Venetian, lived from 1697 to 1768 and became famous in his lifetime for his detailed scenes of Venice, Rome and England.

The picture sold Wednesday is ''The Entrance to the Grand Canal Looking Toward the Bacino.'' It was copied by another artist, whose picture is in the Windsor Castle collection of Queen Elizabeth II. The original was lost in the 18th century.

However, Anthony Weld Forester, 31, a Sotheby's employee in Glasgow, discovered the painting while viewing furniture in a house owned by a deceased businessman, W.A. Shand.

''I thought it looked like an early work of Canaletto and it would be a good idea for the boys in London to see it,'' Forester told a reporter.

It was Forester's second find in Scotland this year.

Six months earlier he spotted in another house a huge oil painting of ''David with the head of Goliath,'' that was identified as an unknown and unrecorded work of the 17th century Bolognese artist, Guido Reni. It was auctioned in April for nearly $2.4 million to a private buyer and is now on a three-year loan to the National Gallery in London.

''Glasgow was the second port after London in the 19th century and there was a lot of money here. Every month something turns up that is worth substantially more than its owners think. I suppose I've become adept at spotting those things,'' Forester said.