TII  .

AST RORHIZIDIACEAE.—Simple forms, rarely polythalamous (some Rhabdamminidae), but often branching or radiate; test arenaceous, loosely compacted and traversed by chinks for pseudopodia (Astrorhizidae), or dense, and opening by one or more terminal pylomes at ends of branches . Marine, Fam . The test of some Asirorhizidae is so loose that it falls to pieces when taken out of water . Haliphysenia is remarkable for its history in relation to the " gastraea theory." Pilulina has a neat globular shell of spongespicules and ' fine sand . Genera, Astrorhiza (Sandahl) in every case gives off granules and irregular masses . -(" chromidia ") of similar reactions, which play an important part in reproduction . During the maturation of the microsphere the nuelei.disappear; and the cytoplasm breaks up into, a large number of zoospores, each of which is soon provided with a single inns leua, whether. entirely derived from the parent-nucleus or front the coalescence 6fehromidia, or from both these sources is still uncertain ... These zoospores are amoeboid ; they soon secrete a shell and reveal themselves as megalospheres, the original state of the megalospheric forms . In the adult megalosphere the solitary nucleus disappears and is re-placed by hosts of minute vesicular nuclei, formed by the.concentration of chromidia . Each nucleus aggregates around it a proper zone of dense protoplasm; by two successive mitotic divisions each mass becomes quadri-nucleate, and splits up into four biflagellate, uninucleate zoospores . These are pairing-cells of gametes, though they will not pair with members of the same brood .

In the zygote resulting from pairing two nuclei soon fuse into one; but this again divides into two; an embryonic shell is secreted, and this Is the microspheric type, which is multinuclear from the first . F . Schaudinn compares the nuclei of the adult

Foraminifera with the (vegetative) meganucleus of Infusora (q.v.) and the chromidial mass with the micronucleus, whose chief function is reproductive . Since megalospheric forms are by far the most abundant, it seems probable that under most conditions they also give rise to megalospheric young like themselves; and that the production of zoospores, (fig . 22), Pilulina (Carptr.) (fig . 19), Saccammin4 (Sars) (fig . 19), Rhabdammina (Sars), Botellina (Carptr.), Hallphysema (Bowerbank) (fig . 22) . IV . LITUOLIDACEAE.—Shell arenaceous, usually fine-grained, definite and often polythalamic, recalling in structure calcareous forms . Lituola (Lamk.) (fig . 19), Endothyra (Phil.), Ammodiscus (Reuss), Loftusia (Brady), Hapl iphragmium (Reuss) (5g .

22), Thurammina (Brady) (fig . 22) . V . MILIoLIDACEAB.—Shells porcellanous imperforate, almost invariably with a camptostyle leading from the embryonic (fig . 23, 3) . IX . GLOBIGERINIDACEAE.—Shells vitreous, coarser perforated;

chambers few spheroidal rapidly increasing in size; arranged in a trochoid or nautiloid spiral . Globigerina (I,amk.) (23, 6; 4, 12); Hastigerina (Wyville Thompson) (fig . 23, a); Orbulina (d'Orb,) (fig . 23, 8) .