Source : Webster's Revised Unabridged Dictionary (1913)

Thunderworm \Thun"der*worm`\, n. (Zo["o]l.)
   A small, footless, burrowing, snakelike lizard ({Rhineura
   Floridana}) allied to Amphisb[ae]na, native of Florida; -- so
   called because it leaves its burrows after a thundershower.