Before the Greatest Clown Alley on Earth was split in two:
Down front: Marcos Drougett
On the ring curb: Mark Anthony, Lazlo Donnert, Frankie Saluto
That looks like a Dewsberry there at the far left. I'm not sure of who's who until we get to Dale Evans and then we have Prof. Paul Wenzel with Miguel "Mike" Padilla in front, Lou Jacobs in his waterskiing outfit and Mike "Coco" Polikovs in his great "harlequin" suit.
If you look closely behind the trombone you'll see Prince Paul Alpert.
Conspicuously absent: Duane Thorpe, Kinko Sunberry, Bobby Kaye, Michael Karp, Dougie Ashton, and Otto Griebling.