The shells of this genus and the three following genera are affixed to
marine bodies by a tough membranous peduncle, varying in length.
Shell flat, with five valves imbricating more or less on the edges,
united by a thin membrane.
Anatifera lævis.
A. villosa.
A. dentata.
A. striata.
A. vitrea.
_A. lævis._ The smooth Anatifera. Pl. 4, fig. 5.
Five smooth valves; the dorsal one rounded at the sides, and slightly
carinated; peduncle long, naked, of a scarlet colour.