I posted this question several years ago, and had everyone stumped then. Thought I'd try again.
Who does the narration as the Captain on the old Submarine Voyage ("...mermaids? I don't believe it....Mr. Baxter, check the air pressure...")
And by the way, I guess it would have been too early to make a reference to Tony Baxter back in 1959 (he would have been just a little kid back then), but I always thought it was fun, regardless.
The voice of the Captain (and, of the host who encourages Tiki Room guests lining up outside its doors to "come with us...to a land of joyous songs, and wondrous miracles...") are two of my top "Disneyland Mysteries"!