Possible Clues:

• ''The New Yorker'' cartoonist Peter
• The Ponte Vecchio bridges it
• ''New Yorker'' cartoonist
• Longtime "New Yorker" cartoonist
• River of 11 across
• River of 4 down?
• Cartoonist who first said 'back to the old drawing board'
• River that flows through Florence
• View from the Ponte Vecchio
• River under the Ponte Santa Trinita