REPORT ON THE RADIOLARIA. 363 



(which genus contaius also a number of other Prunoidea), partly by me (1862) as 

 Didymocijrtis. Both names are inadequate, as allusions to quite different families of 

 Nassellaria, but may be retained as significations of subgeneric divisions. Cyplionium differs 

 from Cijphanta by the diiuble medullary shell, which is either spherical or lenticular. 



Subgenus 1. Ommatospyris, Ehrenberg {partim). 

 Definition. — Surface of the cortical shell smooth, without thorns or spines. 



1. Ci/phonium coscinoides, n. sp. 



Oimnatosj>i/ris coscinoides, Haeckel, 1881, Prodromus, p. 462. 



Cortical shell thin walled, with smooth surface ; pores regular, hexagonal, three to four times 

 as broad as the bars ; five to six on the half meridian, eight to nine on the half equator of each 

 chamber. Medullary shells both spherical. (The cortical shell of this species is nearly the same as 

 that of Cyphanta colpodes, and as the middle part of the cortical shell of Panartus diploconus, 



PI. 40, fig. 1.) 



Dimensions. — Main axis of the cortical shell O'll, equatorial axis 0'06 ; greatest breadth of the 

 chambers 0-08 ; pores 0-013, bars 0-003. 



Habitat. — -North Pacific, Station 244, surface. 



2. Cyphonium virgineum, n. sp. (PI. 39, figs. 12, 12«). 



Ommatospyris virginea, Haeckel, 1881, Prodromus et Atlas (pi. xxxix. fig. 12a). 



Cortical shell tliick walled, with smooth surface (sometimes a little rough with very small 

 thorns) ; pores subregular, circular, with hexagonal elevated frames, about as broad as the bars ; ten 

 to twelve on the half meridian, sixteen to eighteen on the half equator of each chamber. Medullary 

 shells (fig. 12«) both spherical. (Sometimes, as in the figured specimen, the shell is somewhat 

 irregular, an individual aljnormality.) 



Dimensions. — Main axis of the cortical shell O'lS to 0-15; equatorial axis of the structure 

 0-08 to 0-09, of each chamber O'l to 0-12, pores and bars 0005 to 0-007. 



Habitat. — Pacific, western tropical part, Station 225, depth 4475 fathoms. 



.3. Cyphonium ethmarium, n. sp. 



Ommatospyris ethmaria, Haeckel, 1881, Prodromus, p. 462. 



Cortical shell thin walled, with quite smooth surface ; pores subregular, circular (without 

 hexagonal frame), twice as broad as the bars ; nine to ten on the half meridian of each chambei , 

 sixteen to eighteen on its half equator. Medullary shells both spherical. (This species resembles 

 the proximal internal chambers of Peripanartus atr actus, PI. 40, fig. 7.) 



Dimensions. — Main axis 0-13, equatorial axis 007 ; greatest breadth 0-09 ; pores 0-006, 

 bars 0-003. 



Habitat. — -Equatorial Atlantic, Station 347, surface. 



