Cytological Observations on Two Planktonic Foraminifera, Globigerina bulloides d'Orbigny, 1826, and Globigerinoides ruber (d'Orbigny, 1839) Cushman, 1927*†‡

Authors:
Publisher website
Google Scholar
Abstract
SYNOPSIS. Globigerina bulloides and Globigerinoides ruber, two pelagic foraminifera from the North Atlantic, were fixed in modified Zenker or Bouin solutions directly after collection and studied cytochemically. They have two unusual organelles: a vesicular system and an organelle provisionally named a “cryptosome.” The vesicular system occurs chiefly in the newest formed chambers and consists of a pair of intertwined tubules with helical fine structure which terminate in a bouquet of approximately 20 vesicles or loops. The function of this system is unknown. The detailed morphology of the vesicular system is different in each species. The cryptosome is a structure which varies greatly in its morphology. It is better developed in G. bulloides than it is in G. ruber. At times a cryptosome may occupy up to 2/3 of the protoplasm of a chamber. In Himes‐Moriber‐stained preparations crypto‐somes stain with naphthol yellow S and contain within them an azure A‐Schiff staining spongy reticulum. Both of the pelagic foraminifera studied are heterokaryotic. Agamonts of G. ruber may have a graded series of nuclear sizes but those of G. bulloides typically have a single somatic nucleus. The zooxanthellae of G. ruber are similar to Symbiodinium microadriaticum and may collectively occupy almost 4/5 the volume of a chamber.

This publication has 13 references indexed in Scilit: