REPOET ON THE RADIOLARIA. 469 



iireoailar, roinidish ; ten on the radius of the phacoid shell, a single one on each chamber of the 

 ('i|uatorial girdle. Margin of the disk with numerous strong conical radial spines of different 

 breadths, arranged in several circles, the strongest in the equatorial plane, about as broad as one 

 ring and twice as long. Surface tliorny. 



Dimensions. — Diameter of tlie disk (with seven rings) O'.'l, of the jihacoid shell 0-12, of the outer 

 medullary shell O'Oo, of the inner 0-02. 



Habitat. — Pacific, central area, Station 268, depth 290(1 fathoms ; also fossil in Barbados. 



Subfamily 3. Astracturida, Haeckel, 1881, Prodromiis, p. 458. 



Definition. — Co cc o di s c i d ;i with two or more (commonly three or four) 

 chambered radial arms on the margin of the di.sk, .situated in its equatorial plane (with 

 or without a connecting patagiuni between the arms). 



Genus 204. Diplaftnrd.,^ Haeckel, 1881, Prodronuis, p. 458. 



Definition. — C o c c o d i s c i d n with two opposite chambered arms on the margin of 

 the circular disk, without a connecting patagium. 



The genus Dij^lactura is the simplest form of the Astracturida, or uf those 

 Coccodiscida in \\diich the margin of the disk bears chambered arms, situated in its 

 equatorial plane. This sul)family corresponds to the Euchitonida among the Porodiscida, 

 to the Spougobrachida among the Spongodiscida. In Di2)lactura there are only two 

 free arms, opposite in one ec^uatorial diameter (corresponding to AniphibracJmtm among 

 the former, to Spongolene among the latter). 



Subgenus 1. Diplaeturiuni, Haeckel. 

 Definition. — Arms blunt at the distal end, without radial spines. 



1. Diplactura diplohracliia, n. sp. 



Phacoid shell twice as broad as the medullary shell, with six pores mi its radius, without a perfect 

 chambered ring around it. Arms club-shaped, one and a half times as long as the diameter of the 

 [ihaeoid shell, at the distal end rounded, lilunt, as liroad as the latter, at the base only half 

 as liroad. 



Dimensions. — Diameter of the pliacoid shell O'OH, of the medullary shell 0-04; length of the 

 arms 012, basal breadth 004, distal breadth 0-08. 



Sabitat. — Pacific, central area. Station 26.5, depth 2900 fathoms. 



1 Z)iptac(i(ra = Stellated shell with double tail ; arnXovi, cixri':, oi/»«. 



