REPORT ON THE RADIOLARIA. 313 



Subgenus 1. Prunuletta, Haeckel. 



Definition. Network of the cortical shell regular, with meshes of equal size and 

 similar form. 



1. Prunulum fi'uyulum, 11. sp. 



Cortical shell thin walled, smooth, with regular, hexagonal pores, three times as broad as the 

 liars ; ten to twelve on the half equator. Proportion of the major axis of the ellipsoid to the minor 

 = 4:3. Both medullary shells spherical. (Differs from Druppula drupa almost entirely in the 

 double medullary shell.) 



Dimensions. Major axis of the ellipsoidal cortical shell 012, minor 0'09 ; pores 0'006, bars 0'002 ; 

 diameter of both medullary shells 0'05 and 0'03. 



Habitat. Pacific, central area, Station 266, depth 2750 fathoms. 



2. Prunulum cerasum, n. sp. 



Cortical shell thick walled, smooth, with circular, hexagonally framed pores, of the same 

 breadth as the bars ; sixteen to eighteen on the half equator. Proportion of the two axes of the 

 ellipsoid = 5 :4. Both medullary shells spherical. (The cortical shell resembles that of Pipetta 

 I nil". PI. 39, fig. 7, without the polar tubes.) 



Dimensions. Major axis 015, minor 012 ; pores and bars 0'007 ; diameter of the medullary 

 shells 0-08 and 0'04. 



Habitat. South Atlantic, Station 332, depth 2200 fathoms. 



3. Prunulum amygdalum, n. sp. 



Cortical shell thick walled, smooth, with regular, circular, hexagonally lobulated pores, three 

 times as broad as the bars ; twelve to fourteen on the half equator (of the same form as in Druppula 

 piwui.r and in Stauroxiphos r/ladius, PL 15, fig. 7). Proportion of the two axes = 6:5. Inner 

 medullary shell spherical, outer ellipsoidal. 



Dimensions. Major axis 012, minor 01 ; pores 0'009, bars 0'003 ; diameter of the medullary 

 shells 0-07 and O04. 



Habitat. Mediterranean (Corfu), surface. 



4. Prunulum coccymelium (PL 39, fig. 4). 



Cortical shell thin walled, slightly rough, with regular, circular pores, twice as broad as the bars ; 

 twelve to fifteen on the half equator. Proportion of both axes = 4 : 3. Both medullary shells 

 spherical. 



Dimensions. Major axis 012, minor 0'09 ; pores 0'006, bars 0'003 ; diameter of the medullary 

 shells 0-OG and 0'03. 



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



(ZOOL. CHALL. EXP. PART XL. 1885.^ E P 40 



