REPORT ON THE RADIOLARIA. 313 



Subgenus 1. PrunuJetta, Haeckel. 



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

 similar form. 



1. Prunulum frugulum, u. sp. 



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

 bars ; 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 Druppida drupa almost entirely in the 

 doulile medullary shell.) 



Dimensions. — Major axis of the ellipsoidal cortical shell 0-12, 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 cerasuni, 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 tlie two axes of the 

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

 tuba, 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 OIU. 



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 tlie same form as in Dnippula 

 pluenix and in Stauroxiphos f/ladtjts, PI. 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 O'Ol. 



Habitat. — Mediterranean (Corfu), surface. 



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



Cortical sheU 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 0-06 and 003. 



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



(ZOOL. CHALL. EXP. PART XI.. — 1885.) R r 40 



