The Heterohelicacea are middle Jurassic to Oligocene planktonic forams included in the Globigerinidae, characterized by birserial or triserial tests, at least in the early stage, that may be reduced in the later stage but more commonly show chamber proliferation in the later stage. Aperture a low or high arch at the base of the final chamber or te...
Found on http://en.wikipedia.org/wiki/Heterohelicacea
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