Carterina

Carterina is a genus in the family Trochamminidae, composing its own subfamily Carterininae. The genus is described from specimens gathered during the Challenger expedition's circumnavigation of the Earth from 1872-1876.

The test (or shell) of Carterina begins as a low, free, umbilicate trochospiral (concavo-convexly coiled with a central depression) in the early growth stage, becoming attached and spreading irregularly in later stages. Chambers become partially subdivided by secondary septa, reaching as many a 15 per chamber in later chambers.(Loeblich & Tappan 1964, 1988) Walls are composed of two sizes of fusiform spicules of low-Mg calcite, larger structural spicules in a ground mass of smaller spicules. The spicules are secreted by the protoplasm, crystallographic c-axes parallel to the elongation, and set parallel to the test surface.