REPORT ON THE RADIOLARIA. 



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 phseodium in the extracapsular 

 calymma. The Monopylea comprise two orders : 



A. PLECTELLAEIA (without complete lattice-shell). 



B. CYKTELLARIA (with complete lattice-shell). 



IV. CANNOPYLEA or PH^EODARIA. 



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 "phaeodium" 

 in the extracapsular calymma. The Cannopylea comprise two orders : 



A. PH^EOCYSTINA (without lattice-shell). 



B. PH^OCOSCINA (with lattice-shell). 



Synopsis of the four Subclasses or Legions of Radiolaria. 



A. HOLOTRYPASTA. 



Central capsule everywhere perforated by innumer- 

 able small pores. 



Fundamental form originally homaxon (spherical or 

 derived from a sphere). 



B. MEROTRYPASTA 



Central capsule with one large main-opening (with 

 or without small accessory openings). 



Fundamental form originally monaxon (egg-shaped or 

 perhaps dipleural). 



I. 



SPUMELLARIA. 

 (Peripylea.) 



^Vall-pores of the cap- 

 sule equally disposed. 



Skeleton siliceous or 

 wanting. 



Calymma without phaeo- 

 dium. 



II. 



ACANTHARIA. 



(Actipylea.) 



Wall-pores of the cap- 

 sule symmetrically dis- 

 posed. 



Skeleton acauthinic (or- 

 ganic). 



Calymma without phceo- 

 dium. 



III. 



NASSELLARIA. 

 (Monopylea. ) 



Main-opening of the cap- 

 sule with a porous 

 operculum. 



Skeleton siliceous (rarely 

 wanting). 



Calymma without phaeo- 

 dium. 



IV. 



PHAEODAKIA. 

 (Cannopylea.) 



Main-opening of the cap- 

 sule with a short 

 tubule. 



Skeleton siliceous (rarely 

 wanting). 



Calymma constantly with 

 a phseodium. 



