Mantle

Lunate

Monoraphid

The part of a valve that extends from the valve face, forming the edge of the valve. When a frustule is viewed in girdle view, the mantle is visible.

Image Credit: Marina Potapova

The mantle of Aulacoseira alpigena is ornamented, while the valve face has marginal arealae.

Image Credit: Marina Potapova

The mantle of Stephanodiscus yellowstonensis is rounded at the mantle/valve face interface.