54 DE. G. J. HINDE ON THE EADIOLARfA IN THE [Eeb. 1 899, 



the medullary test are rounded ; the radial spines are slender, conical, 

 now unequal in length, probably due to imperfect preservation : the 

 longest equals the radius of the test. The proximal ends of the 

 spines extend for a short distance within the medullary test. 

 Diameter of cortical test, 0-15 by 0*13 mm. ; of medullary, 0*05 mm.; 

 of pores, 0-008 mm. ; longest spine (measured from margin of test) 

 0'07 mm., and thickness, 0-01 mm. Rare. In siliceous limestone. 

 No. 245 3. 



Genus Heliosesteum, Haeckel. 



The test is similar to that of Distriactis, but the radial spines are 

 eight in number ; occasionally there are seven or nine. 



Heliosesteum nigeum, sp. nov. (PI. IX, fig. 13.) 



The test is only shown in section ; it is slightly oval in outline ; 

 the medullary test is about one-third the diameter of the cortical; 

 there are eight radial spines, but only one of these is preserved com- 

 plete ; it is about twice the diameter of the disc, and slightly curved 

 near the end. Diameter of outer test, 0"135 by O'll mm. ; of inner, 

 0-038 mm. ; length of spine, 0*24 mm., and thickness, 0*02 mm. In 

 siliceous limestone. No. 245 3. 



Genus Spongodiscus, Haeckel. 



The test is a flattened disc, of irregularly reticulate or spongy 

 structure throughout, without marginal appendages. 



Spongodiscus punctus, sp. nov. (PI. IX, fig. 14.) 



The disc is nearly circular in outline, with very minute pores 

 and irregularly reticulate framework without radial bars. Diameter, 

 0-14 mm. ; pores, about 0-003 mm. Eare. In volcanic tuff. 



No. 387 D. 



Spongodiscfs acinus, sp. nov. (PI. IX, fig. 15.) 



The test is oval in outline, depressed, the structure minutely 

 reticulate, and the margin is roughened with small prickles. 

 Diameter of test, 0*09 mm. Closely allied to the preceding ; it may 

 be distinguished by its prickly surface and oval outline. Rare. In 

 siliceous limestone. No. 245 3. 



Spongodiscus ceibearius, sp. nov. (PI. IX, fig. 16.) 



The test is nearly circular in outline, depressed ; the reticulate 

 structure is minute, though less so than in the preceding species, 

 and the pores are consequently larger. No radial bars. Diameter 

 of test, 0*2 mm. ; width of pores, 0-005 to 0*01 mm. Rare. 

 In volcanic tuff. No. 387 d. This form may be compared with 

 Sp. eocpansus, Hinde, from the Cretaceous at Fanny Bay, Port 

 Darwin, which has a finer structure.^ 



1 Quart. Journ. Geol. Soc. vol. xlix (1893) p. 224 & pi. v, fig. 6. 



