WHOSE AFRAID OF A SNAKE?: These youngsters were photographed at the Children's Museum, housed in the old Donovan School on Wall St., with some of the museum's live snake specimens. The boy on the extreme left has a cornsnake, the youngster at the right foreground has a kingsnake, and the others have gartersnakes. All of the snakes are harmless. The museum at present is open from 2 to 3 o'clock Monday and Wednesday afternoons and the staff is preparing to hold an open house in the fall. Wildlife and financial contributions to the museum may be arranged by calling the museum, 5856.