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



1. Prunocarpus datura, n. sp. 



Cortical shell thick walled, with regular, circular pores, twice as broad as the bars ; ten to twelve 

 on the half equator. Between every three meshes arises a short conical spine, twice to three times as 

 long as one pore. Both medullary shells spherical. (Differs mainly from Ellipsidium datura and 

 from Di-uppocarpus castanea in the double medullary shell. The outer network resembles Haliomma 

 castanea, figured 1862 in my Monograph, Taf. xxiv. fig. 4.) 



Dimensions. Major axis of the ellipsoid 016, minor 012; pores 0'012, bars O006 ; length of 

 the radial spines 0'03 ; diameter of the medullary shells 0'06 and 0'04. 



Habitat. North Atlantic, Fteroe Channel, John Murray, surface. 



2. Prunocarpus sparganium, u. sp. 



Cortical shell thick walled, with very small, numerous, regular, circular pores, of the same size 

 as the bars ; forty to fifty on the half equator. Between them over the entire surface occur small 

 conical spines. Irregularly scattered over the surface ten to twenty larger conical spines, three to 

 six times as thick at the base as one pore, one-fourth to one-half as long as the main axis. Both 

 medullary shells ellipsoidal. 



Dimensions. Major axis of the cortical shell 016, of the outer medullary shell Oil, of the 

 inner 0'06 ; equatorial axis of the first shell 012, of the second 0'08, of the third 0'04 ; pores and 

 bars on an average 0'005 ; length of the spines 0'05 to 01, basal breadth 0-02 to 0'03. 



Habitat. Fossil in the Barbados deposits (Haeckel). 



Subgenus 2. Prunocarpilla, Haeckel. 



Definition. Network of the cortical shell irregular, with meshes of different size or 

 form. 



3. Prunocarpus artocarpium, n. sp. (PI. 39, fig. 5). 



Cortical shell thin walled, with irregular, roundish pores of very different sizes, twice to nine 

 times as broad as the thin bars ; ten to fifteen on the half equator. Between them arise numerous 

 bristle-shaped, radial spines, with conical base, on an average one-fourth to two-thirds as long as the 

 equatorial axis. The outer medullary shell, with irregular, roundish pores, presents a transverse 

 ellipsoid, its main axis lying in the equatorial axis of the cortical shell, whilst its equatorial axis 

 corresponds to the main axis of the latter. Inner medullary shell very small, spherical, with very 

 small pores. 



Dimensions. Major axis of the cortical shell 014, of the outer medullary shell OD5 ; minor 

 axis of the former 01, of the latter 0'035 ; diameter of the inner medullary shell 0'014; pores of 

 the cortical shell 0'005 to 0'02, bars 0'002 ; length of the radial spines 0'02 to 0'06. 



Habitat. Indian Ocean, surface ; Ceylon, Belligemma, Haeckel. 



