REPORT ON THE RADIOLARIA
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III. MONOPYLEA or NASSELLARIA.
Membrane of the central capsule simple, perforated by a porous-area, or by one single large opening, divided into numerous very fine pores. Fundamental form originally monaxon or egg-shaped. Skeleton siliceous. No phæodium in the extracapsular calymma. The Monopylea comprise two orders:—
A. Plectellaria (without complete lattice-shell).
B. Cyrtellaria (with complete lattice-shell).
IV. CANNOPYLEA or PHÆODARIA.
Membrane of the central capsule double, perforated by one simple main-opening, prolonged into a tubulus, and besides this commonly by one or two (rarely more) small accessory openings. Fundamental form originally monaxon or egg-shaped. Skeleton siliceous. Constantly a peculiar dark pigment-body or "phæodium" in the extracapsular calymma. The Cannopylea comprise two orders:—
A. Phæocystina (without lattice-shell).
B. Phæocoscina (with lattice-shell).
Synopsis of the four Subclasses or Legions of Radiolaria.
| A. HOLOTRYPASTA. | B. MEROTRYPASTA. | ||
| Central capsule everywhere perforated by innumerable small pores. | Central capsule with one large main-opening (with or without small accessory openings). | ||
| Fundamental form originally homaxon (spherical or derived from a sphere). | Fundamental form originally monaxon (egg-shaped or perhaps dipleural). | ||
| I. | II. | III. | IV. |
| Spumellaria. | Acantharia. | Nassellaria. | Phæodaria. |
| (Peripylea.) | (Actipylea.) | (Monopylea.) | (Cannopylea.) |
| Wall-pores of the capsule equally disposed. | Wall-pores of the capsule symmetrically disposed. | Main-opening of the capsule with a porous operculum. | Main-opening of the capsule with a short tubule. |
| Skeleton siliceous or wanting. | Skeleton acanthinic (organic). | Skeleton siliceous (rarely wanting). | Skeleton siliceous (rarely wanting). |
| Calymma without phæodium. | Calymma without phæodium. | Calymma without phæodium. | Calymma constantly with a phæodium. |
