246 THE VOYAGE OF H.M.S. CHALLENGER. 



in Astrosphcera stellata, PL 19, fig. 5, but without radial by-spines); outer shell twice as broad, 

 with simple triangular meshes. Eadial spines with serrated edges and three rows of simple lateral 

 branches (four branches on each edge). 



Dimensions. Diameter of the outer shell O44, inner 0'22. 



Habitat. Tropical Atlantic (Ascension Island), Station 343, surface. 



7. Leptosphcera reticulum, n. sp. 



Inner shell with irregular, polygonal meshes and very thin thread-like bars ; outer shell four 

 times as broad, also with irregular, polygonal meshes, the sides of the triangular main meshes being 

 connected by irregular lateral ramules, forming an extremely delicate reticulum. 



Dimensions. Diameter of the outer shell 0'64, inner 016. 



Habitat. South Pacific, Station 291, surface. 



Genus 98. Diplosphcera, 1 Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. 



Berlin, p. 804. 



Definition. A strosphserida with two extracapsular cortical shells, connected 

 by long, prismatic, radial spines ; inner shell with thin radial by-spines. 



The genus Diplosphcera differs from its ancestral form Leptosphcera in the develop- 

 ment of radial by-spines on the surface of the inner shell, the outer shell being smooth. 



Subgenus 1. Diplosphcerella, Haeckel. 

 Definition. Radial main spines simple, without lateral branches. 



1. Diplosphcera hexagonalis, n. sp. (PI. 19, fig. 3). 



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

 one bristle-shaped by-spine ; outer shell twice as broad, with simple triangular meshes. Eadial 

 spines with three smooth edges. (The radially striped central capsule, enclosed in the inner shell, 

 envelops a large central nucleus one-third its size, fig. 3.) 



Dimensions. Diameter of the outer shell O36, inner 0'18. 



Habitat. Central Pacific, Stations 265 to 274, surface. 



2. Diplosphcera ornata, n. sp. 



Inner shell with regular, hexagonal meshes, four times as broad as the bars ; outer shell three 

 times as broad, with simple triangular meshes. Eadial main spines as well as "the bars of both 



1 niplosph a:ra Double sphere ; 



