FORATRINIF'ERA, a group of marine animals of very low organization, consisting if a gelatinous substance enclosed in a shell, which is generally calcareous, either simple m divided into chambers variously arranged, and pierced with pores or passages foramina, whence the name), through which long delicate processes of the soft animal ire protruded, but for what purpose is not very well known, whether to seize food, to :imbibe nutritive fluid, for locomotion, or for all these purposes. Most of the species ire minute, although one of more than 2 in. in diameter has been found in Borneo, and fossil forms approaching to this size are well known under the name of -nummulites 'q.v.), from their resemblance to coins. The existing species are very numerous, end have been distributed into many genera. They, are found among sea-sand, and mom; all the dredgings of deep water. The fossil species are still more numerous, and .7onstitute great part of some calcareous rocks, as of chalk. The F. are of very beautiful forms. Som.o of the simple ones are orbicular, some curiously flask-shaped; those in which the animal is divided into segments, and the shell consequently chambered, some times have the segments arranged in a straight line, sometimes spirally, sometimes alternately, etc. The great resemblance of some of the convoluted chambered shells of the F. to the shells of the genus nautilus, led Linnnus and many naturalists to rank them with that genus, and the F. were reckoned among the most organized mollusks, a place from which comparatively recent disconries have completely removed them. They are now regarded as more nearly related to sponges and to suchtinimals as the proteus or ameba. " The foraminifera are-evidently composite fabrics evolved by
a process of continuous gemination, each gemnia remaining in connection with. he body by which it was put forth, and according to the plan on which this gemmation takes place will be the configuration of the shell.''—Rymer Jones. Reproduction takes place by the detachment of minute granules in great numbers, and is apparently accompanied with the death of the parent. See PitoTozoA. 4;) Fossil earliest records of this order yet observed are hi sandstones near St. Petersburg, belonging to the lower Silurian measures. Scattered through these sandstones are numerous green grains, which have been shown by Ehrenberg to contain, in their interior, silicious casts of shells similar to the recent genera guttulina and textu laria. Forms, apparently referrible to the last genus and to fusulina, constitute a large portion of some beds of carboniferous limestone in Russia, and also in the United States. Among the secondary rocks, and especially in the chalk, F. are very abundant. Chalk, indeed, is composed almost entirely of the perfect or broken shells of rotalia, spirulina, textularia, etc. (see CHALK). They are not more numerous in the tertiary strata, but here they attain an enormous size—gigantic compared with any that preceded them, or with recent forms. Vast beds of limestone occur on the borders of the Medi terranean, composed almost entirely of these large forms. See NUMIHILITES and Nuas MITLITE LIMESTONE.