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



Subgenus 1. Plegmosphcerantha, Haeckel. 



Definition. Inside and outside of the spongy shell-wall smooth, closed by a 

 lattice-plate with polygonal meshes. 



1. Plegmosphcera maxima, n. sp. 



Radius of the spherical shell-cavity eight to ten times as great as the thickness of the thin 

 spongy wall. Inside and outside of the wall smooth, closed by a lattice-plate with irregular 

 polygonal meshes. Only three or four meshes in the thickness of the wall. 



Dimensions. Diameter of the spongy sphere 0'8 to I'D mm., of its inner cavity 0'7 to 0'8, 

 meshes O'Ol to 0'02, bars 0'002 to 0'003, central capsule 0'5 to 0'6, nucleus 01 to 015. 



Habitat, Central Pacific, Station 271, surface. 



2. Plegmosphcera coelopila, n. sp. 



Radius of the spherical shell-cavity eight to ten times as great as the thickness of the spongy 

 wall. Inside and outside of the wall closed by a smooth lattice-plate with irregular polygonal 

 meshes, five to ten times as broad as the bars. 



Dimensions. diameter of the shell 0'32, of its cavity 0'26, meshes O'Ol to 0'02, bars 0-002. 



Habitat. North Atlantic, Fseroe Channel, Gulf Stream, John Murray. 



3. Plegmosphcera pachypila, n. sp. 



Radius of the spherical shell-cavity about equal to the thickness of the spongy wall. Inside 

 and outside of the wall closed by a smooth lattice-plate with irregular polygonal meshes, three to 

 six times as broad as the bars. 



Dimensions. Diameter of the shell 0'24, of its cavity 012. 



Habitat. North Pacific, Station 250, surface. 



Subgenus 2. Plegmosphcerella, Haeckel. 



Definition. Inside of the spongy shell-wall closed by a smooth lattice-plate, 

 outside rough, spongy, with prominent thorns. 



4. Plegmosphcera entodictyon, n. sp. 



Radius of the spherical shell-cavity half as great as the thickness of the spongy wall. Inside 

 of the wall closed by a smooth lattice-plate, outside rough, spongy. 

 Dimensions. Diameter of the shell 0'24, of its cavity 0'08. 

 Habitat. South Pacific, Station 300, surface. 



