-------------------------------+----------------------------------- A. HOLOTRYPASTA. | B. MEROTRYPASTA. | Central capsule everywhere | Central capsule with one large perforated by innumerable | main-opening (with or without small pores. | small accessory openings). | Fundamental form originally | Fundamental form originally homaxon (spherical or | monaxon (egg-shaped or derived from a sphere). | perhaps dipleural). --------------+----------------+-----------------+----------------- I. | II. | III. | IV. | | | SPUMELLARIA. | ACANTHARIA. | NASSELLARIA. | PHÆODARIA. (_Peripylea._)| (_Actipylea._) | (_Monopylea._) | (_Cannopylea._) | | | Wall-pores of | Wall-pores of | Main-opening of | Main-opening of the capsule | the capsule | the capsule | the capsule equally | symmetrically | with a porous | with a short disposed. | disposed. | operculum. | tubule. | | | Skeleton | Skeleton | Skeleton | Skeleton siliceous | acanthinic | siliceous | siliceous or wanting. | (organic). | (rarely | (rarely | | wanting). | wanting). | | | Calymma | Calymma | Calymma | Calymma without | without | without | constantly phæodium. | phæodium. | phæodium. | with a | | | phæodium. --------------+----------------+-----------------+----------------- {6}LEGION I. #SPUMELLARIA#, VEL PERIPYLEA, VEL PERIPYLARIA (PLS. 1-50). _Spumellaria_ (_exclusis_ Spyridinis), Ehrenberg, 1875. _Peripylea_ (_inclusis_ Thalassicollis et Sphærozois), Hertwig, 1879. _Peripylaria_ (_inclusis_ Collodariis et Polycyttariis), Haeckel, 1881. _Definition._--Radiolaria with simple membrane of the central capsule, which is everywhere perforated by innumerable very fine pores. Extracapsulum without phæodium. Skeleton wanting or siliceous. Fundamental form originally spherical.