REPORT ON THE RADIOLARIA. 247 



shells very elegantly denticulated ; radial by-spines (very numerous in the surface of the inner 

 shell) smooth. 



Dimemions. Diameter of the outer shell 0'7, inner 0'24. 



Habitat. Indian Ocean, Madagascar, surface, Eabbe. 



3. Diplosphcera dictyota, n. sp. 



Inner shell with regular, hexagonal meshes, six times as broad as the bars ; at each nodal-point 

 one radial by-spine ; outer shell two and a half times as broad, with very delicate square meshes, 

 separated by thread-like bars which arise from the sides of the triangular main meshes. Eadial 

 main spines with three serrated edges. (Differs from the similar Diplosphcera gracilis in the simple 

 main spines, with delicate dentition of the edges.) 



Dimensions. Diameter of the outer shell - 5, inner 0'2. 



Habitat. North Atlantic, Canary Islands, surface. 



4. Diplosphcera polygonalis, n. sp. 



Inner shell with irregular, polygonal meshes and very thin thread-like bars, covered with very 

 numerous bristle-shaped by-spines ; outer shell twice as broad, with simple triangular meshes. 

 Eadial main spines with three smooth edges. 



Dimensions. Diameter of the outer shell 0'44, inner 0'22. 



Habitat. South Pacific, Station 288, surface. 



Subgenus 2. Diplosphceromma, Haeckel. 



Definition. Eadial main spines with three rows of lateral branches (one row on 

 each edge). 



5. Diplosphcera gracilis, Haeckel. 



Diplotplicera gracilis, Haeckel, 1862, Monogr. d. Radiol., p. 354, Taf. x. fig. 1. 



Inner shell with regular, hexagonal meshes and very thin bars ; at each nodal-point one simple 

 bristle-shaped radial by-spine ; outer shell twice as broad, with very delicate square meshes, 

 separated by thread-like bars which arise from the sides of the triangular main meshes. Eadial 

 spines with smooth edges and with three rows of simple curved lateral branches (four to six branches 

 on each edge). 



Dimensiom. Diameter of the outer shell O54, inner 0'27. 



Habitat. Mediterranean (Messina). 



6. Diplosphcera denticulata, n. sp. 



Inner shell with regular, hexagonal meshes, four times as broad as the bars ; at each nodal-point 

 is a simple bristle-shaped by-spine ; outer shell three times as broad, with simple triangular meshes. 



