Source : Webster's Revised Unabridged Dictionary (1913)

Parapodium \Par`a*po"di*um\, n.; pl. {Parapodia}. [NL., fr. Gr.
   ? beside + ?, dim. of ? foot.] (Zo["o]l.)
   One of the lateral appendages of an annelid; -- called also
   {foot tubercle}.

   Note: They may serve for locomotion, respiration, and
         sensation, and often contain spines or set[ae]. When
         well developed, a dorsal part, or notopodium, and a
         ventral part, or neuropodium, are distinguished.

Source : WordNet®

parapodium
     n : one of a pair of fleshy appendages of a polychete annelid
         that functions in locomotion and breathing
     [also: {parapodia} (pl)]

parapodia
     See {parapodium}