Biomineralization Within Vesicles: The Calcite of Coccoliths

Biomineralization Within Vesicles 197Figure 4. Coccolithus pelagicus structure details. (A) Complete coccosphere. (B) Light micrographs ofisolated coccoliths in phase contrast (top) and cross-polarized light (bottom), only the proximal shield isbirefringent in this orientation and so the specimen appears smaller than it does in phase contrast. (C)Complete coccolith in proximal view. (D) Oblique proximal view of broken coccolith. (E) Detail of D, withproto-coccolith ring locus visible. (F) Detail of proximal shield from a broken and slightly etched specimenshowing the two layers in this structure (compare with crystal unit diagrams).