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



in Ast rosplimra stdlata, PI 19, tig. 5, but without radial by-sjiines); 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 0'44, inner 0"22. 



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



7. Leftosplicera reticulum, u. sp. 



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



BiviensioTis. — Diameter of the outer shell 0"64, inner 016. 



Habitat .—^owih Pacific, Station 291, surface. 



Genus 98. Dij^losphcera,^ Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. 



Berlin, p. 804. 



Definition. — A s t r o s p li ae r i d a with two extracapsular cortical shells, connected 

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



The genus DvplosiohcBra differs from its ancestral form Leptosphcera in the develojj- 

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



Subgenus 1. DipJospliCBvella, Haeckel. 

 Definition. — Eadial main spines simple, without lateral branches. 



1. DipJosp)licera hexagomdis, 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 liy-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.) 



Divicnsions. — Diameter of tlie outer shell 036, inner 0'18. 



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



2. Dip>lospluera ornata, n. sj?. 



Inner .shell with regular, hexagonal me.shes, four times as l)road as the bars ; outer shell tliree 

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



' 7)?p/os^7/(i)'a = Doul)le .sphere ; Iit>Ms, e(paha. 



