Preliminary observations on Chrysochromulina Mactra sp. nov.

Salient features of interest concerning this new species include its large cell size, characteristic scales, bulging pyrenoids and aspects of its development and geographical distribution. The scales, described in some detail, are individually visible with the light microscope and of two types. The outermost scales are tub- or beaker-shaped and the under scales rimless plates. In both cases their thin texture, surface patterning and appearance in section permit an interpretation to be put forward in terms of relatively simple modifications of two-layered rimless plates. The relevance of these findings to understanding of some living and fossil forms is discussed in a preliminary way.