REPORT ON THE RADIOLARIA. 1601 



Subgenus 2. Orodictyum, Haeckel. 



Definition. — External shell a complex framework, forming an outer spongy envelope 

 around the inner primary shell. 



4. Oroplegma spongiosum, n. sp. (PL 107, fig. 3). 



Eadial spines stout, cylindrical, spinulate, slightly curved, three to tive times as broad as the 

 inner rough bars. External shell witli pyramidal elevations, forming a loose spongy framework, 

 the irregular polygonal meshes of which are two to five times as broad as those of the enclosed 

 internal shell ; the thickness of the spongy envelope equals about half the radius of the inner sliell. 

 External free prolongations of the radial spines about equal to the radius. 



Dimensions. — Diameter of the inner sphere 2 to 2"5, of the outer 3 to 35 ; length of the free 

 radial spines 0'5 to 2-0, breadth 01. 



Edbitat — North Pacific, Station 241, depth 2300 fathoms. 



5. Oroplegma giganteum, n. sp. (PI. 107, fig. 2). 



Eadial spines slender, cylindrical, spinulate, irregularly curved, about twice as broad as the 

 spinulate tubidar bars of the network (fig. 2). External shell an irregitlar, loose, spongy framework, 

 the polygonal meshes of which are three to six times as broad as the rounded irregidar meshes of 

 the inner shell ; the tliickness of the spongy envelope about equals the radius of the inner shell. 

 External free prolongation of the radial spines irregularly branched. 



Dimensions. — Diameter of the inner sphere 3"2 to 3-5, of the outer 5'4 to 6'6 ; length of the 

 free spines 1"4 to I'o, breadth 0"03. 



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



Family LXXV. SAGOSPH.i;RiDA, n. fam. (PL 108). 



Definition. — Ph^odakia with a large spherical (or sometimes polyhedral), very 

 delicate shell, which is composed of solid, very thin and long threads. Nodal points of 

 the arachnoidal network without astral septa. Meshes large, triangular. Surface of the 

 shell usually armed with radial spines and often studded with pyramidal elevations. No 

 peculiar mouth in the shell. Central capsule tripylean, in the centre of the shell. 



The family Sagosphserida comprises a rather large number of common and widely 

 distributed Ph^odaria, which in respect of the special form and differentiation of the 

 shell exhibit the greatest similarity to the common Aulosphserida, but diff'er essentially 

 from them in the peculiar structure of the network. This is not composed of stout 

 hollow cylindrical tubes, but of solid, very thin threads ; and these fine arachnoidal 



(ZOOL. CHALL. EXP. — PAKT XL. — 1886.) El 201 



