EEPORT ON THE RADIOLARIA. 139 



Dime-nsions. — Diameter of the outer spliere O'OS, pores and bars O'OOO ; inner sphere O'O.'l ; 

 length of the major polar spine 0'15 to 0'25, of the minor 0'07 to 0-09, breadth 0'02. 

 H(diit((t. — Fossil in the Barljados rocks. 



3. Sphcerostylus clioj ii. sp. 



Cortical shell tliick walled, with smooth surface, twice as broad as the medullary shell ; its 

 network has regular, circular pores, three times as broad as the bars ; sixteen to twenty on the half 

 equator. Polar spines very strong, three-sided pyramidal ; the major nearly twice as long as tlie 

 axis of the outer sphere, the minor scarcely as long as its radius. (Nearly related to Stylosphcera 

 did, V\. 16, fig. 7, but differs in the slender form and unequal length of the polar spines.) 



Dimensions. — Diameter of the outer sphere 014, pores 0-01, bars 0-03 ; inner sphere 0'07 ; 

 length of the major spine 0-25, of the minor 0-06, basal breadth 0'02. 



Hahitat. — Pacific, centi-al area. Station 274, depth 2750 fathoms. 



4. Splice I'ostylus hippocampus, ru sp. (PI. 16, figs. 10, 11). 



Cortical shell thick walled, with smooth surface and regular network ; the piores circular, 

 liexagonally-lobed, three times as broad as the bars ; ten to twelve on the half equator 

 iledullary shell half as large, with very small circular pores, eight to ten on the half equator, 

 ilajor polar spine scarcely as long as the axis of the outer shell, curved like a horn ; minor spine 

 scarcely half as long, pommel-like, edged. (Sometimes, by prolongation of the main axis, 

 the spherical shells become ellipsoidal and thus the species is transformed into Druppatractus hipiw- 

 campus.) 



Bimemicms. — Diameter of the outer sphere 0-08, pores O'OOO, bars O'OOo ; inner sphere 01)4; 

 length of the major spine 0'07, of the minor 0'03, breadth 0'02. 



Habitat. — Pacific, central area. Station 270, depth 2925 fathoms. 



Subgenus 2. SphcBrostyletta, Haeckel. 



Definition. — Pores of the cortical shell regular, of nearly equal size and form ; surface 

 spiny or thorny. 



5. Spluerostylus diadema, n. sp. 



Cortical shell thick walled, spiny, twice as broad as the medullary shell, with regular, circular 

 pores, twice as broad as the bars ; eight to ten on the half equator. Major polar spine about as 

 long as the axis of the outer sphere, three-sided pyramidal ; minor spine scarcely half as long, 

 pommel-shaped, edged. (Similar, in general form, to Xip)ha.tractus glyptodon, PI. 17, figs. 9, 10 ; 

 bvu differs in the simple medullary sliell, the spherical form of both shells, and the simple circular 

 regular pores.) 



