REPORT ON THE RADIOLARIA. 79 



1. Thecosphcera triplodictyon, n. sp. 



Cortical shell thin walled, smooth, with regular, hexagonal pores, four times as broad as the bars. 

 Radial proportion of the three spheres = 1 : 2 : 8. Both medullary shells with regular circular 

 pores, twice as broad as the bars, the inner half as broad as the outer. All three shells connected 

 by six thin radial beams, opposite in pairs in the three dimensive axes. 



Dimensions. Diameter of the outer shell 0'2, middle 0'05, inner - 025 ; cortical pores 0'012, 

 bars 0-003. 



Habitat. Central Pacific, Station 271, surface. 



2. Thecosphcera phcenaxonia, n. sp. 



Cortical shell thick walled, rough, with regular, circular, hexagonally framed pores, twice as 

 broad as the bars. Eadial proportion of the three spheres = 1:2:6. Both medullary shells with 

 regular hexagonal pores and thin bars. All three shells connected by six prismatic radial beams, 

 opposite in pairs in the three dimensive axes. (Shell similar to Hexacontium sceplrum, PL 24, 

 fig. 1, la, but without external spines.) 



Dimensions. Diameter of the outer shell 012, middle 0'04, inner 0'02 ; cortical pores O'Ol, 

 bars 0-005. 



Habitat. North Pacific, Station 253, surface. 



3. Thecosphcera favosa, n. sp. 



Cortical shell thick walled, thorny, with regular, circular, hexagonally framed pores, of the same 

 breadth as the bars. Eadial proportion of the three spheres = 1 : 3 : 10. Both medullary shells 

 with regular circular pores, connected with the former by twelve short prismatic, regularly disposed 

 radial beams. 



Dimensions. Diameter of the outer shell 0'2, middle 0'06, inner 0'02 ; cortical pores and bars 

 0-008. 



Habitat. Central Pacific, Station 268, surface ; also fossil in Barbados. 



4. Thecosphcera floribunda, n. sp. 



Cortical shell thick walled, smooth, with regular, elegantly six-lobed pores, three times as broad 

 as the bars. Eadial proportion of the three spheres = 1:2:4. Both medullary shells with simple 

 regular circular pores, connected with the former by six dimensive radial beams. (Similar to Hexa- 

 contium floridum, PL 24, fig. 4, but without external spines.) 



Dimensions. Diameter of the outer shell 0'12, middle 0'06, inner 0'03 ; cortical pores O'Ol, 

 bars 0-0033. 



Habitat. Central Pacific, Station 266, depth 2750 fathoms. 



