The Collaborative International Dictionary of English v.0.48:

Osphradium \Os*phra"di*um\, n.; pl. Osphradia. [NL., fr. Gr. ?
   strong scent, fr. ? to smell.] (Zool.)
   The olfactory organ of some Mollusca. It is connected with
   the organ of respiration.
   [1913 Webster] Osprey