REPORT ON THE RADIOLARIA. 357 



Dimensions. — Main axis 0'12, equatorial axis 0'07 ; meshes 0'004 to 0'02, bars 0'002 to O'OOS ; 

 spines 0-01 to 002. 



Habitat. — Atlantic, Eastern Tropical part, Station 346, surface. 



Genus 153. Stylartus,'^ Haeckel, 1881, Prodromus, p. 462. 



Definition. — Artiscida with two strong, solid, polar spines, or two bunches of 

 polar spines, opposite on the two poles of the main axis. 



The genus Stylartns differs from Artiscus hy the production of two large opposite 

 spines in the main axis, starting from Ijoth poles of it ; sometimes every spine is sur- 

 rounded Ijy a group of smaller radial spines. The genus is nearly allied to Ellipsoxiphus 

 (p. 295), and diflers from it only in the equatorial stricture of the ellipsoidal shell. But 

 it may also l)e derived from tlie similar Cyphinu.'i (PI. 39, fig. 14) by loss of the 

 medullary .shell. 



Subgenus 1. Sti/lartella, Haeckel. 

 Definition. — On each pole of the main axis only one single large spine. 



1. Stylartus hiiMaris, u. sp. (PI. 48, fig. 5). 



Shell thick walled, rough ; both its chambers nearly spherical, with irregular, roundish pores, 

 twice to four times as broad as the bars ; eight to ten on the half equator of each chamber. Polar 

 spines very strong, conical, as long as the greatest breadth. 



Dimensions. — Length of the shell (without spines) O'lS, greatest breadth Olo ; length of tlie 

 polar spines 013, basal breadth 0-03. 



Hahitat. — Western Tropical Pacific, Station 224, depth 1850 fathoms. 



2. Stylartus bicuspis, u. sp. 



Shell thin walled, smooth, with regular, circular pores, twice as broad as the bars; twelve to 

 fourteen tjn the half equator of eacli chamber. Polar spines very stout, straight, three-sided 

 pyramidal, half as long as the shell. 



Dimensions. — Length of the shell 0-16, greatest breadth 0-12 ; length of the polar spines 0-08, 

 basal thickness 0'025. 



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



Suljgenus 2. Stylartura, Haeckel. 

 Defi,nition. — On each pole of the main axis a bunch of several spines. 



' S(i/iart?w = Bread witli styles ; (jtJ>.o;. citro;. 



