BISERIAMMINA Chernysheva, 1941

 

 

Type species: Biseriammina uralica Chernysheva, 1941; OD.

Biseriammina Chernysheva, 1941 (*582), p. 69.

Test free, chambers biserially arranged, with planispirally enrolled axis of biseriality, so that the few subglobular chambers alternate from side to side as added; wall calcare­ous, microgranular; aperture a narrow interiomarginal slit against the previous chamber, in a nearly equatorial position and a short distance above the contact of the cham­ber with those of the preceding whorl. L. Carboniferous (Tournaisian); USSR: Ural Mountains; Bashkirian ASSR.