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



Subgenus 1. Plegmosphoerantha, Haeckel. 



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

 lattice-plate with polygonal meshes. 



1. Plegmosphcera maxima, n. sp. 



Eadius of the spherical shell-cavity eight to ten times as gi-eat as the thickness of the thin 

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

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



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

 meshes 0-01 to 0-02, bars 0-002 to 0-003, central capsule 0-5 to 0-6, nucleus 0-1 to 0-15. 



Habitat. — Central Pacific, Station 271, surface. 



2. PlegmosphcBra coelopila, n. sp. 



Eadius 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 Q-Ol to 0-02, bars 0-002. 



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



3. PlegmosphcBra pachypila, u. sp. 



Eadius 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 0-12. 



Habitat. — North Pacific, Station 250, surface. 



Subgenus 2. PlegmosphcErella, Haeckel. 



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

 outside rough, spongy, with prominent thorns. 



4. PlegmosphcBra entodictyon, n. sp. 



Eadius of the spherical sheU-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 O'OS. 

 Habitat. — South Pacific, Station 300, surface. 



