Salenia (Salenia) geometrica (Agassiz, 1838)
Members of the subfamily Saleniinae (Agassiz) (e.g. Salenia geometrica and Bathysalenia granulosus) are characterised by small tests, a fused apical disc, and a small, pronounced periproct. Mature individuals of Salenia geometrica are distinguished from Bathysalenia granulosus by the smooth appearance of the apical disc, whereas that of B. granulosus has a distinctly granular appearance. Salenia geometrica ranges from the Late Santonian to Early Campanian.
1). Salenia geometrica (x9, Worthing area, White Chalk, Randell Collection, RR1514); (A) adapical and (B) adoral views. Small notches (sutural pits) are present between the apical plates.
2). (A) Lateral (side) view of the above specimen (x9). (B) Adoral view of a juvenile specimen (x14, Worthing area, White Chalk, Randell Collection, RR1519). Notice how the sutural pits are much larger relatively speaking than in the adult specimen (1(A)), giving the apical disc a sieve-like appearance.