Publication Date:
2017-07-24
Description:
Three closely related species ( A. beccarii (Linn.), A. batava (Hofker) and A. tepida (Cushman) have been studied. Each possesses a multilaminate “chitinoid” endoskeleton, the outermost lamina possessing imperforate pustulae of shape characteristic for the species. The pustulae are fused to segmented tubules of organically-bound carbonate granules; these tubules line the canaliculi linking the inner and outer perforations of the test wall, and differ only in length between the three species. The calcareous wall is essentially granular in internal morphology, and is built upon an organic framework in which the tubules play a significant part. The apertural structures are described, and it is confirmed that the toothplate is structurally continuous with the septal (“rotalid”) flap and the basal calcareous lamella of the test. The distribution of
intrathalamous and extrathalamous cytoplasm in A. tepida is described, and the first sequential photographs of cytoplasmic extrusion are presented for Ammonia. The relationship between the organic skeleton, the calcareous exo- and endo-skeletons, and the cell, is discussed.
Type:
Article
,
PeerReviewed
Format:
text
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