The Collaborative International Dictionary of English v.0.48:

Ear-shell \Ear"-shell`\, n. (Zo["o]l.)
   any of various large edible marine gastropod mollusks of the
   genus Haliotis, having a flattened ear-shaped shell with a
   pearly interior; -- called also sea-ear. See Abalone.

   Syn: abalone.
        [1913 Webster + WordNet 1.5]

WordNet (r) 3.0 (2006):

ear-shell
    n 1: any of various large edible marine gastropods of the genus
         Haliotis having an ear-shaped shell with pearly interior
         [syn: abalone, ear-shell]