312 THE VOYAGE OF H.M.S. CHALLENGER. 



3. Druppocarpus chamaerops, n. sp. 



Cortical shell thin walled, with irregular, roundish, or subcircular pores of very different size, 

 twine to six times as broad as the thin bars ; eight to twelve on the half equator. Between them 

 arise numerous thin, bristle-like radial spines, about half as long as the equatorial axis, and equal 

 to the diameter of the spherical medullary shell ; pores of the latter subregular, circular, very small. 

 (Resembles Prunocarpus artocarpus, PL 39, fig. 5, but differs in the simple spherical medullary 



shell.) 



Dimensions. Major axis 012, minor O09 ; meshes 0'005 to 0'02, bars 0'003; length of the 

 radial spines O05 ; diameter of the medullary shell 0'04 



Habitat. Mediterranean, in the Strait of Gibraltar, Algesiras, Haeckel, surface. 



4. Druppocarpus borassus, n. sp. 



Cortical shell thick walled, with irregular, roundish, or subcircular pores, three to five times as 

 broad as the bars ; twelve to fifteen on the half equator. Irregularly scattered on the surface about 

 twenty to thirty short conical spines ; their length equals their basal breadth and the diameter of 

 the largest pores. Medullary shell ellipsoidal, half as large as the cortical. 



Dimensions. Major axis 01, minor 0'08 ; pores O'OOG to O'Ol, bars 0'002 ; length and thickness 

 of the radial spines O'Ol ; axes of the medullary shell 0'05 and 0'04. 



Habitat. Pacific, central area, Station 268, depth 2900 fathoms. 



5. Druppocarpus corypha, n. sp. 



Cortical shell thick walled, with irregular, funnel-like, roundish pores, scarcely as broad as the 

 bars ; sixteen to twenty on the half equator. Irregularly scattered on the surface about fifteen to 

 twenty three-sided pyramidal radial spines, half as long as the equatorial axis, and as the diameter 

 of the medullary shell. 



Dimensions. Major axis 017, minor 014 ; pores and bars O'OOS to 0'009 ; length of the radial 

 spines 0'08 ; diameter of the medullary shell 0'09. 



Habitat. Fossil in the Tertiary rocks of the Nicobars, Haeckel. 



Genus 133. Prunulum, 1 n. gen. 



Definition. Druppulida with simple ellipsoidal cortical shell and double 

 medullary shell ; without spines or polar tubes. 



The genus Prunulum differs from Druppula in the double (not simple) medullary 

 shell, which is sometimes spherical, sometimes ellipsoidal; it may be derived either 

 from Druppula by duplication of the medullary shell, or from Thecosphcera by pro- 

 longation of one axis. 



1 PrnijJm=Little-phun. 



