3. Lituolidaceae: test arenaceous, often symmetrical or regularly spiral, isomorphous with calcareous forms: the chambers when old often "labyrinthine" by the ingrowth of wall-material. Lituola, Lam.; Reophax, Montf.; Ammodiscus, Reuss; Trochammina, Parker and Jeffreys.

4. Miliolidaceae: test porcellanous, imperforate, spirally coiled or cyclic, often chambered except in Cornuspira: simple in Squamulina. Cornuspira, Max Sch.; Peneroplis, Montf.; Miliolina, Lam. (incl. Biloculina (Fig. 15), Triloculina, Quinqueloculina (Figs. 14, 4; 15, B), Spiroloculina (Fig. 13, 5) of d'Orb.); Alveolina, d'Orb.; Hauerina, d'Orb.; Calcituba, Roboz; Orbitolites, Lam.; Orbiculina, Lam.; Alveolina, Park. and Jeffr.; Nubecularia, Def.; Squamulina, Max Sch. (Fig. 14, 3).

5. Textulariaceae: test calcareous, hyaline, perforated; chambers increasing in size in two alternating rows, or three, or passing into a spiral. Textularia, Def.; Bulimina, d'Orb.; Cassidulina, d'Orb.

6. Cheilostomellaceae: test vitreous, delicate, finely perforated, chambered, isomorphic with the spiral forms of the Miliolidaceae. Cheilostomella, Reuss.

7. Lagenaceae: Test vitreous, very finely perforate, chambers with a distinct pylome projecting (ectosolenial), or turned in (entosolenial), often succeeding to form a necklace-like shell. Lagena, Walker and Boys (Fig. 13, 2); Nodosaria, Lam. (Fig. 13, 3); Cristellaria, Lam.; Frondicularia, Def. (Fig. 13, 4); Polymorphina, Lam.; Ramulina, Wright.

8. Globigerinidae: test vitreous, perforate; chambers few, dilated, and arranged in a flat or conical spiral, usually with a crescentic pylome to the last. Globigerina, d'Orb. (Figs. 13, 6; 16, 2); Hastigerina, Wyv. Thoms.; Orbulina, d'Orb. (Fig. 16, 1).

9. Rotaliaceae; test vitreous, perforate, usually a conical spiral (like a snail), chambers often subdivided into chamberlets, and with a proper wall, and intermediate skeleton traversed by canals. Rotalia, Lam. (Fig. 14, 2); Planorbulina, d'Orb. (Fig. 13, 9); Polytrema, Risso; Spirillina, Ehr. (non-septate); Patellina, Will.; Discorbina, P. and J. (Fig. 13, 7).

10. Nummulitaceae: test usually a complex spiral, the turns completely investing their predecessors: wall finely tubular, often with a proper wall and intermediate skeleton. Fusulina, Fisch.; Polystomella, Lam.; Nummulites, d'Orb. (Fig. 13, 11); Orbitoides, d'Orb.

The Allogromidiaceae are a well-marked and distinct order, on the whole resembling the Rhizopoda Filosa, and are often found with them in fresh water, while all other Foraminifera are marine. The type genus, Allogromia (Fig. 14, 1), has an oval chitinous shell. Microgromia socialis (Fig. 11) is often found in aggregates, the pseudopodia of neighbours fusing where they meet into a common network. This is due to the fact that one of the two daughter-cells at each fission, that does not retain the parent shell, remains in connexion with its sister that does: sometimes, however, it retracts its pseudopodia, except two which become flagella, wherewith it can swim off. The test of Pamphagus is a mere pellicle. In Lieberkühnia (Fig. 12) it is hardly that; though the body does not give off the fine pseudopodia directly, but emits a thick process or "stylopodium"[[78]] comparable to the protoplasm protruded through the pylome of its better protected allies; and from this, which often stretches back parallel to the elongated body, the reticulum of pseudopodia is emitted. Diaphorodon has a shell recalling that of Difflugia (Fig. 10, D, p. [55]), formed of sandy fragments, but with interstices between them through which as well as through the two pylomes the pseudopodia pass. In all of these the shell is formed as in the Rhizopods once for all, and does not grow afterwards; and the fresh-water forms, which are the majority, have one or more contractile vacuoles; in Allogromia they are very numerous, scattered on the expanded protoplasmic network.