epipodium

from The Century Dictionary.

• noun In some Echinoidea, a raised ring surrounding each pair of pores on each primary ambulacral plate.
• noun One of the appendages of the side of the foot of certain mollusks, as the odontophorous or cephalophorous univalves; some lateral part or process of the foot, in any way distinguished from the mesial propodium, mesopodium, and metapodium.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) One of the lateral lobes of the foot in certain gastropods.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun zoology One of the lateral lobes of the foot in certain gastropods.