REPORT ON THE RADIOLARIA. 1599 



6. Oroscena huxleyi, n. sp. (PI. 12, figs. 1, la). 



Eadial spines cylindrical, obliquely ascending and irregularly curved, about as long as the 

 diameter of the shell and somewhat thicker than its thorny bars. A variable number of short, 

 irregular, partly simple, partly forked, lateral branches arises from the spines. Meshes of the 

 network very irregular, partly solid, partly hollow (fig. la*), the majority quadrangular. This species, 

 the first observed form of Orosphaerida (captured the 21st February 1873 at Station 5), was at the 

 beginning of my observations, in 1876, and when I had no knowledge of the central capsule, 

 erroneously regarded by me as a gigantic Sphseroid (of the Monosphasrida) and therefore placed 

 in PL 12. The long branched spines, afterwards observed complete in another specimen, were 

 broken off in the specimen first figured. 



Dimensions. Diameter of the shell 2'0 to 2'5, length of the spines 2 to 3 mm., breadth 0'03. 



Habitat. North Atlantic (west of Canary Islands), Station 5, depth 2740 fathoms. 



7. Oroscena darwinii, n. sp. 



Eadial spines cylindrical, irregularly curved and branched, about twice as long as the diameter 

 of the shell ; the branches are all again ramified and partly confluent (as in PL 107, fig. 1). The 

 branches and the bars of the network are of equal breadth, smooth (not thorny as in the similar 

 preceding species). Meshes rather subregular, quadrangular. 



Dimensions. Diameter of the shell 24 to 2'8, length of the spines 4 to 5 mm., breadth 0'015. 



Habitat. Tropical Atlantic, Station 348, depth 2450 fathoms. 



8. Oroscena duncanii, n. sp. 



? Hexactinellida didyonina, Martin Duncan, 1881, Journ. Eoy. Micr. Soc., p. 175, pi. iii. figs. 4, 6. 



Eadial spines cylindrical, thorny, arborescent, somewhat shorter than the diameter of the shell, 

 with irregular ramified branches (similar to Orosphcera arborescens, PL 1Q6 ) fig. 3). The size and 

 ramification of the arborescent spinulate branches decrease towards the apex. The thicker branches 

 are from two to three times as broad as the spinulate bars of the network. Meshes of the latter 

 irregular, the majority quadrangular. 



Dimensions. Diameter of the shell 3'2, length of the spines 3'5 to 4'5, breadth 0'02 to 0'3. 



Habitat. South Atlantic, Station 318, depth 2040 fathoms ; coast of Portugal, 1095 fathoms. 



Genus 674. Oroplegma, 1 n. gen. 



Definition. Or osphser ida with a spongy, spherical or slightly polyhedral 

 lattice-shell, which is enveloped by a loose spongy framework and bears numerous 

 radial spines. 



The genus Oroplegma differs from the other Orospheerida in the development of an 

 external lattice-work enveloping the internal primary shell, and produced by the union 



1 Oroplegma= Hilly shell of framework; o>j, 



