Source : Webster's Revised Unabridged Dictionary (1913)

Coenurus \C[oe]*nu"rus\, n. [NL. fr. Gr. ? + ? tail.] (Zo["o]l.)
   The larval stage of a tapeworm ({T[ae]nia c[oe]nurus}) which
   forms bladderlike sacs in the brain of sheep, causing the
   fatal disease known as water brain, vertigo, staggers or gid.

   Note: This bladder worm has on its surface numerous small
         heads, each of which, when swallowed by a dog, becomes
         a mature tapeworm in the dog's intestine.