REPORT ON THE RADIOLARIA. 279 



Dimensions. Diameter of the sphere 0'9, of the central cube 0'02; length of the spines 015, 

 distal thickness 0'02. 



Habitat. South Pacific, Station 295, surface. 



Genus 119. Octodendron, 1 n. gen. 



Definition. A strosphaerida with a single, cubical medullary shell, and 

 eight primary radial spines arising from its eight corners ; these are connected at equal 

 distances by a latticed, spherical, cortical shell, from which the spongy framework 

 directly springs ; often from the latter secondary radial spines arise. 



The genus Octodendron has the same regular, cubical medullary shell as the pre- 

 ceding Centrocubus, but differs from it in the wide interval separating the medullary 

 shell from the inner spherical face of the spongy cortical shell, the two being connected 

 only by eight radial beams, arising from the eight corners of the cube. 



Subgenus 1. Octodendridium, Haeckel. 



Definition. Only eight primary radial spines, arising from the eight corners of the 



central cube. 



/ 



1. Octodendron cubocentron, n. sp. (PI. 18, fig. 3). 



Eadial spines eight, club-shaped, with three denticulate, straight edges, twice as long as the 

 diameter of the central cavity of the cubical spongy shell ; the inner face of the latter (or the 

 " inner cortical shell ") exhibits the form of a large cube, the spongy sides of which are parallel with 

 the simple square sides of the central cube. The thin eight radial beams, connecting the correspond- 

 ing corners of both cubes, are not thicker than the edge-bars of the central cube, whilst their outer 

 prolongations are much thicker, with four to six verticils of lateral branches. Surface of the thin 

 walled, loose, spongy shell armed with short simple thorns. 



Dimensions. Diameter of the spongy shell - 2, of its inner cavity 01, of the central cube 0'02 ; 

 length of the spines 0'2 (from the centre 0'3). 



Habitat. Central Pacific, Station 266, surface. 



2. Octodendron spirale, n. sp. 



Eadial spines eight, three-sided prismatic, three times as long as the diameter of the inner 

 shell-cavity ; their three edges denticulated and spirally contorted around the spine axis. Thick- 

 ness of the loose spongy shell-wall equal to the radius of the inner cavity, three times as large as 

 the central cube. Surface covered with numerous thin, bristle-shaped, bent spinules. 



1 Octodendron = Shell with eight trees ; Sx.ru, Bsi/Sjon. 



