foraminifer

noun

1. Any of a large group of aquatic amoeboid protists of the subphylum Foraminifera, characterized by streaming granular ectoplasm that among other things is used for catching food, often with a calcareous shell with many holes through which pseudopodia protrude.

   “The species of foraminifer which composes, almost to the exclusion of all others, the deep Atlantic mud, is called Globigerina. […] The natural home of the foraminifers appears to be in the deeper parts of the ocean, commencing where the regular inhabitants of limited depths terminate.”

   “The Heterostegina-bed at Malta is not without smaller Foraminifers (some of which we can identify,—as the Globigerina bulloides, Truncatulina lobatula, &c.), but the matrix is too stubborn to yield all its treasures.”

   “From a palæontological point of view the only part of a Foraminifer with which we have to deal is the shell or "test," […] Each bud of the compound Foraminifer is surrounded by its own shell, so that the whole comes to be composed of a number of chambers, each containing a mass of sarcode.”

   “The environmental significance of foraminifer abundance variations in Arctic cores is controversial[…]. One interpretation concludes that foraminifer-rich intervals represent interglacial conditions reflecting seasonally absent or reduced ice cover leading to increased productivity; intervals barren or nearly barren of foraminifers are considered to represent glacial conditions with thicker ice cover and lower productivity[…].”

   “A cross-section through a single agglutinated foraminifer – in this case, one that selected both carbonate and non-carbonate grains to build its test. These foraminifers are recognizable by the chamber-shaped grain arrangements rather than the otherwise random distribution of grains in the rest of the rock.”