REPORT ON THE RADIOLARIA. 119 



2. Clathrosphcera arachnoides, n. sp. (PI. 8, fig. 7). 



Inner shell spherical, with irregular roundish meshes, two or three times as broad as the bars. 

 Ten to twelve meshes in the half meridian of the shell. From its surface arise numerous conical 

 radial spines (with base often fenestrated), which at equal distances from the surface send out 

 lateral branches. All these branches lie on a spherical face, and form by communications the irregular, 

 very delicate, arachnoid network of the outer shell, quite unlike that of the inner, with large 

 polygonal meshes of very different size. Eight to sixteen meshes in the half meridian of the shell. 

 Surface of the outer shell nearly spherical, somewhat uneven, like a spider's web. The radius of 

 the inner shell bears to that of the outer a ratio = 3 : 4. 



Dimensions. Diameter of the inner shell 0'12 to 0'14, of the outer 0'15 to 0'18 ; pores of the 

 inner shell 0'003 to 0'02, of the outer O'Ol to 0'04. 



Habitat. Central area of the Tropical Pacific, Station 268, depth 2900 fathoms. 



3. Clathrosphcera lamellosa, n. sp. (PI. 8, fig. 8). 



Inner shell spherical or subspherical, with irregular roundish meshes, about half as broad as 

 the bars. Twelve to sixteen meshes in the half meridian of the shell. From its surface arise 

 numerous oblique irregular staffs or broad and thin lamellae, which branch quite irregularly, and by 

 communications of the branches form the thin outer shell. This is quite irregular roundish or 

 subspherical, very unlike the inner, with large polygonal meshes of different size, six to twelve in 

 the half meridian of the shell. Bridges between the meshes very variable, now very thin fila- 

 mentous, now very broad lamellar. Outer surface very uneven or tuberculated, but not spinous. 

 The radius of the inner shell bears to that of the outer a ratio = 5:6. 



Dimensions. Diameter of the inner shell O'l to 0'13, of the outer 0'12 to 0'18 ; pores of the 

 inner shell O'OOS to 0'009, of the outer O'Ol to 0'04. 



Habitat. Central area of the Tropical Pacific, Stations 270 to 274, depths 2350 to 2925 fathoms. 



Genus 44. Xanthiosphcera, 1 Haeckel, 1881, Prodromus, p. 472. 



Definition. C ollosphserida with a double lattice-shell around every centra] 

 capsule of the ccenobium ; surface of the outer shell thorny or spiny. 



The genus Xanthiosphcera differs from the foregoing Clathrosphcera by spines or 

 thorns arising from the surface of the outer shell, commonly very irregular. 



1. Xanthiosphcera capillacea, n. sp. 



Inner shell spherical, with irregular polygonal meshes, three to five times as broad as their 

 narrow bars. Six to eight meshes in the half meridian of the shell. From its surface arise at the 

 nodes of the network numerous thin radial spines, which, at equal distances from the surface, 



