REPORT ON THE RADIOLARIA. 655 



2. Pylonium hexazonium, n. sp. 



Cortical shell smooth, without symmetrical radial spines. Transverse girdle elliptical, one 

 and a lialf times as long as broad. Lateral and sagittal girdles nearly circular. Four gates 

 egg-shaped. 



Dimensions. — Principal axis 0"16, transverse axis 015 ; diameter of the subspherical medullary 

 shell 0-04. 



Habitat. — South Pacific, Station 295, depth 1500 fathom.s. 



3. Pylonium nephropylium, n. sp. 



Cortical shell thorny, without radial spines. All its three girdles elliptical, one and a third 

 times as long as broad. Four gates kidney-shaped, nearly twice as broad as high. 



Dimensions. — Principal axis OlV, tiuusverse axis 0'13 ; length of the lentelliptical medullary 

 shell 0-04, breadth 0-03. 



Habitat. — Pacific, central area, Station 273, depth 2350 fathoms. 



Subgenus 2. Pylonura, Haeckel. 

 Definition. — Cortical shell armed with large, symmetrically disposed spines. 



4. Pylonium quadricorne, n. sp. (PL 9, fig. 14). 



Cortical shell thorny, with four strong horn-like curved spines in the lateral plane. All its 

 three girdles elliptical, one and a third times as long as broad. Four gates kidney-shaped, twice as 

 broad as high. (This species is a further developmental stage of Tdrwpyh quadricornis, with perfect 

 sagittal girdle.) 



Dimensions. — Principal axis 0'16, transverse axis 0"12 ; length of the medullary shell 0"05, 

 breadth 0-04. 



Habitat. — Pacific, central area. Stations 270 to 274, surface ; Indian Ocean, Madagascar, Rabbe, 

 surface. 



5. Pylonium octacanthum, n. sp. 



Cortical shell thorny, with eight long and thin cylindrical radial spines, lying in two crossed 

 diagonal planes, opposite in pairs, and arising from the eight points where the transverse girdle is 

 crossed by the lateral girdle. All three girdles elliptical, one and a half times as long as broad ; 

 four gates triangular. (This species is a further developmental stage of TdiYqiylc odacantha, with 

 perfect sagittal girdle.) 



Dimensions. — Principal axis OlS, transverse axis 0-13 ; length of the medullary shell 0'03 

 to 0-04. 



Habitat. — Cosmopolitan ; Mediterranean, Atlantic, Pacific, surface. 



