REPORT ON THE RADIOLARIA. 277 



betweeu the two shells, while the two following verticils, by communication of their ramules, form 

 the irregular framework. Central capsule with many hernise, forced out through the meshes of the 

 medullary shell (fig. 5). 



Diviensimis.—'Diametev of the spongy shell 0'7, of its inner cavity 0"45, of the medullary shell 

 0-07. 



Habitat. — South Pacific, Station 284, surface. 



Genus 117. Lychiiosphm^a,^ Haeckel, 1881, Prodromus, p. 453. 



Definition. — A s t r o sphter i d a with a single, spherical, latticed medullary shell, 

 which is armed wdtli free radial by-spines, and connected by stout radial main spines 

 with tlie spongy cortical shell. 



The genus Lychnosphcera, known only by one single, large, and very remarkable 

 species, mainly differs fi-om the foregoing in the development of free radial by-spines on 

 the surface of the medullary shell, and in the free interval between it and the cortical 

 shell ; but beyond this the loose spongy framework of the latter exhibits a very 

 remarkable structure, figured in PI. 11. 



1. lA/chnosphcera regina (P\. 11, figs. 1—4). 



MeduUary shell (fig. 3) with regular, circular, hexagonaUy framed pores, twice as broad as the 

 bars ; from each hexagon-corner arises a radial, bristle-shaped by-spine, as long as the diameter. 

 Twelve radial main spines, each as broad as one of the meshes, three-sided prismatic, six to eight times 

 as long as the medullary shell. From their three leaf-shaped (often somewhat denticulated or spirally 

 contorted) edges arise four verticils of lateral branches, each composed of three forked, thin 

 branches. The forked branches of the first verticil end free between the two shells (figs. 2, 3), while 

 the two following verticils are ramified, and, by anastomosis of tlieir branches, compose the loose 

 spongy framework of the cortical shell. On the surface of the latter arise numerous radial (zig-zag- 

 shaped) by-spines. The fourth verticil is terminal, with three shorter, thicker, dentated, simple 

 branches, which constitute, together with the distal apex of the spine itself, a bunch of four terminal 

 spines. The large central capsule completely distends the medullary shell, and forces out by its 

 pores numerous club-shaped hernia? (fig. 1). 



Dimensions. — Diameter of the spongy cortical shell 0-6, of its inner cavity 04, of the central 

 capsule 022, of the medullary shell 0'06 ; length of the radial spines 0'4, breadth 001. 



Habitat. — Central Pacific, Station 271, surface. 



Genus 118. Centrocuhus,^ n. gen. 



Definition. — A s t r o s p h ae r i d a with a single, cubical medullary shell, immediately 

 surrounded by the spongy framework of the cortical shell ; from the eight corners 



1 L)/c/i)iosp/i(rrti = Lautern-sphere ; 'hCxuoi, atpal^u. 



2 Centrocubus = Shell with a central cuhe ; xt*Tf ok, xi/ios- 



