Very usually, but not universally, the metapodium carries an operculum.
The foot is long, carrying the oblong visceral mass upon it, and projecting (as metapodium) a little beyond it(f).
A strong ligamentous band behind the metapodium, arising from near the upper extremity of its posterior surface, divides into two at its lower end, and each division, being first connected with one of the paired upper sesamoid bones, passes by the side of the first phalanx to join the extensor tendon of the phalanges.