REPOET ON THE RADIOLARIA. 627 



Genus 278. Larnacostupa,^ n. gen. 



Definition. — L a r n a c i cl a with spong}^ lentelliptical cortical shell, with radial 

 spines on the surface. Medullary shell double, Zo /-ttac/ZZo -shaped. 



The genus Larnacostupa differs from the preceding Larmacospongus only in the 

 possession of radial spines, covering either the whole surface irregularly or disposed in 

 a certain symmetrical order. 



1. Larnacostupa octacantha, n. sp. 



Cortical shell lentelliptical, with thorny surface, and rather dense, irregular, spongy framework, 

 which arises from an inner latticed cortical shell, like that of Tdrapijlc or Pylonium. This latter 

 is twice as large as the enclosed Larnacilla-slviW.. Eight long and thru, cylindrical, radial spines, 

 opposite in pairs in two diagonal planes. (Seems to be the common Tctrapyle odacantJia, enveloped 

 by an outer spongy framework mantle.) 



Dimensions. — Length of the whole shell (without spines) 0'22, breadth O'lO ; length of the 

 medullary shell 0"06, breadth 0'04. 



Habitat. — Indian Ocean, Madagascar, Eabbe, surface. 



2. Larnacostup>a s2nnosa, n. sp. 



Cortical shell lentelliptical, about one and a half times as long as broad, with ^-ery lax and 

 irregiilar spongy framework, arising from a nearly quadrangular lattice-shell like that of Tctrapyle ; 

 this latter encloses a Lanuwilla-shQW of half its size. Whole surface covered with thin bristle-like 

 radial spines, of about the length of the shell. 



Dimensions. — Length of the whole shell (without spines) O'lS, breadth 0'12 ; length of the 

 medullary shell O'Oo, breadth 0'035. 



Habitat— Awtavciic Ocean, off Kerguelen, Station 150, surface. 



3. Larnacostuim dendrophora, n. sp. 



Cortical shell nearly spherical, scarcely longer than liroad, with la.x, irregular spongy frame- 

 work, arising, from a lentelliptical trizonal medullary shell (like LarnacUla). Whole surface 

 covered with thin arborescent radial spines, about half as long as the shell, each spine witli three 

 to six irregular "branches. 



Dimensions. — Length of the whole shell (without spines) 0'15, breadth 013 ; length of the 

 medullary shell 007, breadth 004. 



Habitat. — Antarctic Ocean, Station 154, surface. 



1 Lariiacostwpa = Qhi9i with hemp envelop; Kapvai,, uru-Trti. 



