REPORT ON THE RADIOLARIA. 353 



Dimensions. — Length of tlie cortical shell 0-18, breadth 0'14; thickness of its wall 0'035 ; 

 diameter of the outer medullary shell 0'04, of the inner 0'02. 

 Hahitat. — South Atlantic, Station 325, surface. 



6. Spongollva daturina, u. sp. 



Cortical shell one and a half times as long as broad, armed with very numerous, thick and 

 short, conical radial spines, about as long as the outer medullary shell. Spongy framework 

 compact, with small meshes, its thickness equal to half the length of the outer ellipsoidal 

 medullary shell. 



Dimensions. — Length of the cortical shell 0'24, breadth 016 ; thickness of its wall 0'025 ; 

 diameter of the outer medullary shell 0'045 to 0-035, of the inner 0'025. 



Hahitat. — Pacific, central area. Station 272, surface 



Genus 151. Spongoxvphus} n. gen. 



Definition. — S p o n g u r i d a with spongy ellipsoidal cortical shell, enclosing a 

 double, spherical or ellipsoidal, latticed medullary shell. On the poles of the axis occur 

 tw^o opposite strong spines. 



The genus Spongoxiplius difters from Spongollva by the development of two strong 

 spines in the axis of the shell, on its two opposite poles. From the similar Spo7iga- 

 tractus it differs in the duplication of the medullary shell. It may also be regarded 

 as a Stylatractus, in which the simple latticed cortical shell is replaced by an irregular 

 spongy framework. 



1. Spongoxiphus sphcerococcus, n. sp. 



Cortical shell one and a half times as long as broad, with thorny surface. Spongy framework 

 compact, with small meslies, its thickness equal to the radius of tlie outer medullary shell. Both 

 medullary shells spherical, the outer three times as broad as tlie inner. Polar spines very stout, 

 conical, slightly sulcated, about half as long as the cortical shell, as broad at the base as the 

 outer medullary shell. (Differs from Spongatractus pcuih-ystylus almost only in the double medullary 

 shell.) 



Dimensions. — Length of the cortical shell CIS, breadth 0'12 ; thickness of the spongy wall 

 0"025 ; diameter of the outer medullary shell 0-05, of the inner 0'016. 



Habitat. — Fossil in the rocks of Barbados (Haeckel) ; also living in the Pacific, central area. 

 Station 265, depth 2900 fathoms. 



' .SpOJjg'Oxip/lM = Spongy sword ; nvoyyo;, ^I'fOf. 

 (;00L. CHALL. EXP. — PART XL. — 1S85.) Er 45 



