Source : Webster's Revised Unabridged Dictionary (1913)

Natterjack \Nat"ter*jack`\, n. (Zo["o]l.)
   A European toad ({Bufo calamita}), having a yellow line along
   its back.

Source : WordNet®

natterjack
     n : common brownish-yellow short-legged toad of western Europe;
         runs rather than hops [syn: {Bufo calamita}]