REPORT ON THE RADIOLARIA. 357 



Dimensions. Main axis 012, equatorial axis 0'07 ; meshes O004 to O02, bars 0'002 to O'OOo ; 

 spines O'Ol to 0'02. 



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



Genus 153. Stylartus, 1 Haeckel, 1881, Proclromus, 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 Stylartus differs from Artiscus by the production of two large opposite 

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

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

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

 it may also be derived from the similar Cyphinus (PL 39, fig. 14) by loss of the 

 medullary shell. 



Subgenus 1. Stylartella, Haeckel. 

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



1. Stylartus bipolaris, n. 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. 



Diincnswns.Lengtli of the shell (without spines) 018, greatest breadth 013 ; length of the 

 polar spines 013, basal breadth 0'03. 



Habitat. Western Tropical Pacific, Station 224, depth 1850 fathoms. 



2. Stylartus bicuspis, n. sp. 



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

 fourteen on 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 016, greatest breadth 012 ; length of the polar spines 0'08, 

 basal thickness 0'025. 



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



Subgenus 2. Stylartura, Haeckel. 

 Definition. On each pole of the main axis a bunch of several spines. 



1 Stylartus = Bread with styles ; <JT?/O?. 



