EEPORT ON THE RADIOLARIA. 133 



Dimensions. — Diameter of the sphere 0'08, pores 0-006, hars O'OOS ; diameter of the circular 

 ring 016 ; length of the radial spines 0-02 to 0-04 ; thickness of the ring and the axial heams 0-01. 

 Habitat. — Fossil in the Barbados rocks. 



6. Saturnalis rotula, n. sp. (PI. 13, fig. 15). 



Pores of the spherical shell regular, circular, twice as broad as the bars ; sixteen to twenty on 

 the half equator. Eiug cii'cular, armed with fifteen to twenty strong, conical, ii-regiilar sj^ines, 

 partly simple, partly divided into two or three irregular branches ; diameter of the ring two and a 

 half times as gTeat as that of the sphere. 



Dvmensio'tis. — Diameter of the sphere O'OS, pores 0'004, bars 0'002 ; diameter of the circulai' 

 ring 0^2, length of its spines 0'02 to 0'03 ; thickness of the ring and the radial beams O'Ol. 



Habitat. — North Pacific, Station 244, surface. 



Subfamily Sph^rostylida, Haeckel, 1881, Prodromiis, pp. 449, 451. 

 Definition. — S t y 1 o s p h se r i d a with two concentric, spherical lattice-shells. 



Genus 48. Stijlosphcera,^ Ehrenberg, 1847, Monatsber. d. Berlin Akad., p. 54. 



Definition. — S t y 1 osp h se r id a with two concentric lattice-spheres and two free 

 spines of equal size and similar form. 



The genus Stylosi^hcBra, the most simple form of the Sphserostylida, can be derived 

 either from Xiphosphcera by duj)lication of the spherical shell, or from Caiyosphcera 

 by development of two opposite polar sjaines. The inner or medullary shell is enclosed 

 in the central capsule, whilst the outer or cortical shell lies outside it ; the two are con- 

 nected by two or more radial beams, piercing the wall of the capsule. 



Subgenus 1. StylosphcBrantlia, Haeckel. 



Definition. — Pores of the cortical shell regular, of nearly equal size and similar 

 form ; surface smooth or a little rough, without spines or thorns. 



1. Stijlosph(Bra niusa, n. sp. 



Eadial proportion of the two concentric spheres = 3 : 1. Cortical shell thin waUed, smooth, with 

 regular, hexagonal pores, three times as broad as the thin bars ; twelve on the half equator. Polar 

 spines three-sided pyramidal, as long as the axis of the cortical shell, one-tenth as broad at the base. 



Dimensions. — Diameter of the outer shell 0'2, pores O'Ol, bars O'OOo ; diameter of the inner 

 shell 0-06 ; length of the polar spines 0'2, basal breadth 0-02. 



Hahitat. — Tropical Atlantic, Station 347, depth 2250 fathoms. 



' Stylosplimra = B]ihtxt with styles ; ati'ha;, ai^al'^a. 



