Same Alveolina with dimensions annotated. polished specimen.

Same Alveolina , as enlargement below, with dimension annotated.. Polished specimen.

Alveolina in Mixon Limestone of the Western Tethys, UK

Oblique sub-equatorial polished section of Alveolina in Mixon Limestone from off Sussex coast, Owers Bank,
English Channel. Probably Bartonian of the Western Tethys. Maximum dimension of foram is 2.9MM.