Microstructures of cephalis of Cyrtocapsella tetrapera Haeckel (Radiolaria)

Abstract

Microstructures on the surface and fracture surface of cephalic wall and cephalic skeleton of Cyrtocapsella tetrapera Haeckel are observed. Through the observation, the following three lines of evidence are clarified; (1) four patterns of growth lines are recognized in cephalic wall and cephalic skeleton, (2) traces of the vertical, apical and secondary lateral rays are recognized, (3) elongated rays of cephalic skeleton are recognized in cephalic wall. The evidence suggests the possibility that the vertical, apical and secondary lateral rays are gradually covered by lamellae as they grow older.