This is a Sikorsky S-38. A quote gleamed from it's Wikipedia Page explains it nicely.
"The Sikorsky S-38This particular aircraft (this might actually be a replica, not sure) is
was an American twin-engined 8-seat amphibious aircraft. It was
sometimes called 'The Explorer's Air Yacht' and was Sikorsky's first
widely produced amphibious flying boat which in addition to serving
successfully for Pan American Airways and the U.S. Army, also had
numerous private owners who received notoriety for their exploits."
the "Osa's Ark", which belonged to Martin an Osa Johnson, two American
explorers. There is a whole gallery of original photographs of this