Letter | Published:

Classification of Spiral Foraminifera

Nature volume 155, page 81 (20 January 1945) | Download Citation



THE members of certain pairs of foraminiferal genera (Nummulites and Operculinoides, Assilina and Operculina, etc.) with flat spiral tests are distinguished from each other only by the rates (or angles) of opening of their spires. It therefore seems anomalous that no ruling exists as a guide in separating forms after this manner; for although the right allocation is often obvious, there are intermediate forms which might, at present, be as legitimately referred to one genus as to the other, in each of these pairs.

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  1. Grant Institute of Geology, University of Edinburgh. Nov. 20.

    • L. M. DAVIES


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