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



Subgenus 3. Raphidodrymus, Haeckel. 



Definition. — Pores of the spherical shell irregular, of different size or form. Radial 

 spines arising from all the nodal-points of the network. 



18. Acanthosphcera capillaris, n. sp. 



SheU thin walled, with irregular polygonal meshes, twelve to twenty times as broad as the hars ; 

 eight to ten on the radius. Radial sj^iues bristle-shaped, arising from all the nodal-pouits of the 

 network, about as long as tlie diameter of the largest meshes. 



Dimensions. — Diameter of the shell 0'15 to 0'2, pores 0'012 to 0'02, bars 0-001 ; length of the 

 spines 0'02. 



Habitat. — Central Pacific, Stations 260 to 274, surface. 



19. Acanthosphcera arctica, n. sp. 



Shell thin waUed, with irregular roundish, polygonally framed meshes, three to four times as 

 broad as the bars. Eadial si^ines arising from all the nodal-points of the network, pyramidal at 

 the base, in the distal half bristle-shaped, as long as the radius. 



Dimensions. — Diameter of tbe shell 012, pores 0-006 to 0-008, bars 0-002; length of the 

 spines 0-07. 



Habitat. — Arctic Ocean, Greenland (in the stomach of PeriphyUa hyacinthina). 



20. Acanthosphcera antarctica, n. sp. 



Shell thick walled, with irregular, roundish pores, about as broad as the bars. Eadial spines 

 arising from all nodal-points of the network, conical at the base, half as long as the radius. 



Dimensions. — Diameter of the shell 0-15, pores and bars 0-005 to 0-008 ; length of the 

 spines 0-04. 



Habitat. — Antarctic Ocean, Station 157, depth 1950 fathoms. 



Subgenus 4. Rhaphidosphcera, Haeckel, 1881, Prodromus, p. 450. 



Definition. — Pores of the spherical shell irregular, of difl'erent size or form. Eadial 

 spines scattered at intervals, not at aU the nodal-points. 



21. Acanthosphcera echinoides, Haeckel. 



Cyrtidosplicera echinoides, Haeckel, 1865, Zeitschr. f. wiss. Zool, xv. p. 367, Taf. xxvi. fig. 5. 



Shell thin walled, with irregular polygonal or more rounchsh pores of very different size. Forty 

 to fifty very large meshes, separated by rows of much smaller meshes. Radial spines forty to sixty, 

 half as long as the shell radius, bristle-shaped, with conical bases. 



