REPORT ON THE RADIOLARIA. 281 



Dimensions. Diameter of the spongy sphere 1 mm., of its central cavity 015, of the central 

 cube 0'02 ; length of the spines 1 to 1*2 mm., breadth 0-008. 

 Habitat. Central Pacific, Station 271, surface. 



Subgenus 2. Octodendronium, Haeckel. 



Definition. Radial spines thirty -two or more, eight primary (arising from the eight 

 corners of the central cube) and twenty -four or more secondary (between them). 



6. Octodendron verticillatum, n. sp. 



Eadial spines thirty-two, with three denticulate straight edges, six to eight times as long as the 

 diameter of the shell-cavity ; the distal parts half free. Eight primary spines arise from the eight 

 corners of the central cube, twenty-four secondary from the edges of these (a verticil of every three 

 from each primary spine). Distal free parts of all thirty-two spines equal. Each spine with eight 

 to ten verticils of forked lateral branches, without spathillse. Surface of the spongy sphere covered 

 with short simple bristles. 



Dimensions. Diameter of the spongy shell 0'3, of its cavity O12, of the central cube 0*02 ; 

 length of the spines 07 to 1 mm., breadth 0'02. 



Habitat. South Pacific, Station 291, surface. 



7. Octodendron contortum, n. sp. 



Eadial spines thirty-two, disposed in a similar manner to those of the former species (eight 

 primary and twenty-four secondary) ; also the spongy shell of the same shape. The difference 

 arises in the form of the spines, the three edges of which are much broader and spirally contorted 

 around the axis ; and thus the corresponding branches of the verticil do not lie in the same meridian- 

 plane, but alternate one with another. 



Dimensions. Diameter of the spongy shell 0'4, of its cavity Ol, of the central cube O02 ; length 

 of the spines O'S to 1'2, breadth O04. 



Habitat. Central Pacific, Station 274, surface. 



8. Octodendron arboretum, n. sp. 



Eadial spines sixty to ninety, three-sided prismatic, with spirally contorted and denticulate 

 edges, six to eight times as long as the diameter of the inner shell-cavity. Eight primary arise from 

 the eight corners of the central cube, twenty-four others from their three edges (as in the two 

 former species) ; the remaining thirty to sixty spines seem to arise between the former and 

 immediately from the dense spongy framework, which is twice as thick as the diameter of the inner 

 shell-cavity. The numerous verticils of the free distal part are of equal shape in all the spines, 

 composed of three forked branches in the terminal, and of more ramified branches in the inferior 

 parts. Entire surface of the spongy shell covered with simple radial bristles, without spathillse. 



(ZOOL. CHALL. EXP. PART XL. 1885.) Er 36 



