706 THE VOYAGE OF H.M.S. CHALLENGEK. 



7. Streblonia pulvinulina, n. sp. 



Shell top-shaped or flatly conical, with thirty to forty chambers of slowly increasing size, the 

 tenth chamber about three times as broad as the first. Breadth of the shell exceeds three times 

 the height. Pores circular, subregular, very small, about one-third as broad as the bars ; about 

 thirty in the breadth of the tenth chamber. (Resembles closely Pulvinulina.) 



Dimensions. Breadth of the shell - 25, height 0'08. 



Habitat. Pacific, central area, Station 263, depth 2650 fathoms. 



Genus 311. Streblacantha, 1 n. gen. 



Definition. S treblonida with simple, spherical, subspherical, or lentelliptical 

 primordial chamber, beginning the screw -like series of spirally ascending chambers. 

 Surface covered with radial spines. 



The genus Streblacantha differs from the nearly allied Streblonia only in the 

 covering of radial spines, and bears therefore the same relation to it as Hastigerina 

 has to Globigerina amongst the similar calcareous Polythalamia. 



1. Streblacantha siderolina, n. sp. (PL 49, figs. 8, 80). 

 Streblonia siderolina, Haeckel, 1883, MS. 



Shell flatly conical, with fourteen to sixteen nearly hemispherical chambers of gradually increas- 

 ing size, the tenth chamber about six times as broad as the first. Breadth of the shell nearly equal 

 to the height. Pores subregular, circular, hexagonally framed, twice as broad as the bars ; about 

 nine pores on the breadth of the tenth chamber. Surface covered with numerous short conical 

 radial spines, one-fourth to one-sixth as long as the diameter of the shell. 



Dimensions. Breadth of the shell 015, height 017. 



Habitat. South Pacific, Station 298, depth 2225 fathoms. 



2. Streblacantha calcarina, n. sp. 



Shell conical, with sixteen to eighteen roundish chambers of gradually increasing size, the 

 tenth chamber about three times as broad as the first. Breadth of the shell about one and a half 

 times the height. Pores irregular, roundish. Surface covered with numerous strong conical radial 

 spines, about half as long as the diameter of the shell. 



Dimensions. Breadth of the shell 0'24, height 017. 



Habitat. South Pacific, Station 285, depth 2375 fathoms. 



with spines ; <7Tjs'/3Xj, ax.av6a. 



