V. MILIOLIDACEAE.--Shells porcellanous imperforate, almost invariably with a camptostyle leading from the embryonic chamber; _Cornuspira_ (Schultze) (fig. 3); _Miliola_ (Lamk.), including as subgenera _Spiroloculina_ (d'Orb.) (figs. 3 and 22); _Triloculina_ (d'Orb.) (fig. 3); _Biloculina_ (d'Orb.) (fig. 3); _Uniloculina_ (d'Orb.); _Quinqueloculina_ (d'Orb.); _Peneroplis_ (Montfort) (figs. 22, 3; 3), with form _Dendritina_ (fig. 4, 1); _Orbiculina_ (Lamk.) (fig. 3, 6-8); _Orbitolites_ (Lamk.) (figs. 5, 6); _Vertebralina_ (d'Orb.) (fig. 22); _Squamulina_ (Sch.) (fig. 22); _Calcituba_ (Schaudinn). [Illustration: Modified from F. Schaudinn, in Lang's Zoologie. FIG. 17.--Life Cycle of _Polystomella crispa_. A, Young megalospheric individual. B, Adult decalcified. C, Later stage, resolving itself into two flagellate gametes. D, Conjugation. E, Microspheric individual produced from zygote. F, The same resolved itself into pseudopodiospores which are growing into new megalospheric individuals. 1, Principal nucleus, and _2_, subsidiary nuclei of megalospheric form. 3, Nuclei. 4, Nuclei in multiple division. 5, Chromidia derived from 4.] VI. TEXTULARIADACEAE.--Shells perforate, vitreous or (in the larger forms) arenaceous, in two or three alternating ranks (distichous or tristichous). _Textularia_ (Defrance) (fig. 21). VII. CHEILOSTOMELLACEAE.--Shells vitreous, thin, the chambers doubling forwards and backwards as in _Miliolidae_. _Cheilostomella_ (Reuss). VIII. LAGENIDACEAE.--Shells vitreous, often sculptured, mono-or polythalamic, finely perforate; chambers flask-shaped, with a protruding or an inturned stylopyle; _Lagena_ (Walker & Boys) (fig. 4, 9); _Nodosaria_ (Lamk.) (figs. 23, 4; 4, 10); _Polymorphina_ (d'Orb.) (fig. 4, 13); _Cristellaria_ (Lamk.) (fig. 4, 11); _Frondicularia_ (Def.) (fig. 23, 3). IX. GLOBIGERINIDACEAE.--Shells vitreous, coarsely perforated; chambers few spheroidal rapidly increasing in size; arranged in a trochoid or nautiloid spiral. _Globigerina_ (Lamk.) (23, 6; 4, 12); _Hastigerina_ (Wyville Thompson) (fig. 23, 5); _Orbulina_ (d'Orb.) (fig. 23, 8). X. ROTALIDACEAE.--Shells vitreous, finely perforate; walls thick, often double, but without an intermediate party-layer traversed by canals; form usually spiral or trochoid. _Discorbina_ (Parker & Jones) (fig. 4, 15); _Planorbulina_ (d'Orb.) (fig. 4, 17); _Rotalia_ (Lamk.) (figs. 23, 1, 2; 7, 21); _Calcarina_ (d'Orb.) (fig. 23, 10); _Polytrema_ (Risso) (fig. 23, 9). [Illustration: Fig. 18.--_Biloculina depressa_ d'Orb., transverse sections showing dimorphism. (From Lister.) a, Megalospheric shell X 50, showing uniform growth, biloculine throughout. b, Microspheric shell X 90, showing multiform growth, quinqueloculine at first, and then multiform.]