REPORT ON THE RADIOLARIA. 797 



Tlie Central Capsule of the Sphserocapsida is splierical, constantly smaller than the 

 enclosing concentric shell, and separated from it by the calymma. Its structure seems ■ 

 to be the same as in the A c a n t h o n i d a, and specially in the Astrolonchida. The 

 pseudopodia (not yet observed) are probably protruded only through the twenty 

 perspinal holes or the eighty aspinal pores. 



Synopsis of the Genera of SphoBroeapsida- 



I. Subfamily 



Astrocapsida. 

 Radial spines connected with the - 

 porous shell, as long or longer than 

 its radius. Eighty aspinal pores.- 



II. Subfamily 



Porocapsida. 

 Radial spines not connected with the 

 porous shell, shorter than its radius. 

 Twenty perspinal pores. 



Spines as long as the radius, without external 



prolongation, .... 344. Sphoerocapsa. 



Spines longer than the radius, with external 

 prolongation, .... 345. Astrocapsa. 



Perspinal holes of the sheU' simple, without 



external prolongation, . . . 346. Porocapsa. 



Perspinal holes of the shell prolonged into radial 



centrifugal tubuli, .... 347. Cannocapsa. 



III. Subfamily | Twenty perspinal holes of the shell simple, 



Cenocapsida. ^ without tubular prolongation, . . 348. Cenocapsa. 



Kadial spines disappeared'. ) r o ■ 



Subfamily 1. Astkocapsida, Haeckel. 



Definition. — Eadial spines connected with the porous shell, as long as or longer 

 than its radius. Therefore the shell pierced by eighty aspinal pores (four around each 

 spine). - 



Genus 344. SjykcBrocapsa,^ Haeckel,. 1881, Prodromus, p. 469. 



Definition. — S phserocapsida with twenty radial spines as long as the radius 

 of the shell, without external prolongation ; therefore their distal ends inserted in the 

 perspinal holes, each of which is composed of four aspinal pores. 



The genus Sp}i(Brocap>sa is the most common form of the Sphaerocapsida, and 

 comprises those species in which the radial spines are as long as the radius of the shell, 

 and therefore are connected with the margin of its aspinal holes, but not prolonged 

 beyond its surface. 



1 /SpAcEroca^'si = Spherical capsule ; a^oti^ct, xai^a. 



