REPORT ON THE RADIOLARIA. 71 



Dimensions. Diameter of the shell O'l, length of the tubes 0'04, breadth O'Ol, basal distance O01. 

 Habitat. Indian Ocean, Cocos Islands, surface, Eabbe. 



Genus 18. Sethosphcera, 1 Haeckel, 1881, Prodromus, p. 452 (sensu emendato). 



Definition. L iosphserida with one single latticed sphere, with simple shell- 

 cavity ; with shell-pores, which are prolonged on the inside into centripetal, conical, or 

 cylindrical tubuli. 



The genus Sethosphcera differs from its ancestral form, Cenosphcera, by the pro- 

 duction of internal, centripetal, radial tubuli on the inside of the shell (the contrary of 

 the preceding genus Ethmosphcera). It corresponds therefore to the social Pharyngo- 

 sphcera; but in the latter the formation of the shell and its tubes is more or less 

 irregular, whilst in the former each regular pore is prolonged into a regular tubule. 



1. Sethosphcera entosiphonia, n. sp. 



Shell with smooth surface and regular circular pores, separated by hexagonal frames, twice as 

 broad as the bars. Six to eight on the quadrant. Each pore is prolonged on the inside of the shell 

 in a short conical centripetal tube, twice as long as its diameter. 



Dimensions. Diameter of the shell 0'15, outer pores O'OOS, bars 0'004, length of the tubuli 0-015. 



Habitat. Central Pacific, Station 272, depth 2600 fathoms. 



2. Sethosphcera entosolenia, n. sp. 



Shell with smooth surface and regular circular pores, without hexagonal frames, of about the 

 same breadth as the bars. Ten to twelve on the quadrant. Each pore is prolonged on the inside 

 of the shell into a thin cylindrical centripetal tube, three times as long as its diameter, 



Dimensions. Diameter of the shell - 2, outer pores and bars - 006, length of the 

 tubuli 0-02. 



Habitat. Central Pacific, Station 268, depth 2900 fathoms. 



Subfamily CAKPOSPH^ERIDA, 2 Haeckel, 1881, Prodromus, p. 449. 



Definition. Liosphserida with two concentric spherical lattice-shells, which 

 are united by radial beams. 



Carposphcera? Haeckel, 1881, Prodromus, p. 451. 



Definition. L iosphserida with one medullary (intracapsular) and one cortical 

 (extracapsular) shell, both connected by radial beams piercing the central capsule. 



1 SethospJiasra Sieve-sphere ; arifos, <?<p&i(>a. 



2 Carposphserida = Liosphaerida duplicia = Dyosphaerida anacantha. 



3 Carposphcera Fruit-shaped sphere, 



