REPORT ON THE RADIOLARIA. 163 



Dimensions. Diameter of the cortical shell 0'12, medullary shell 0'025 ; pores of the former 0'03, 

 bars O004 ; length of the major spines 012, minor 0'03. 

 Habitat. Fossil in Barbados. 



Genus 66. Stauroxiphos, 1 n. gen. 



Definition. Stau rosphaerida with two concentric lattice-spheres and four 

 crossed simple spines, one of which is much larger than the other three. 



The genus Stauroxiphos differs from its ancestral form, Staurolonche, in the greater 

 development of one single spine, and exhibits therefore the same relation to it that 

 Stylostaurus bears to Staurosphcera. 



1. Stauroxiphos gladius, n. sp. (PI. 15, fig. 7). 



Cortical shell thick walled, smooth, three times as broad as the medullary shell. Pores of the 

 outer shell regular, circular, regularly six-lobed on the outer opening, four times as broad as the 

 bars ; about six on the quadrant. Pores of the inner shell only one-third as large, simple, circular. 

 Three of the four radial spines of nearly equal size, pommel-shaped, with three prominent, dentated 

 wings, somewhat shorter than the shell radius and about half as broad as long ; the fourth spine 

 much larger, sword-like, about three times as long as the shell radius. 



Dimensions. Diameter of the outer shell 0~12, of the inner O04 ; pores of the former O'Ol, bars 

 0-0025 ; pores of the latter OD03, bars O'OOl ; length of the major spine 0"18, of the three 

 minor - 04. 



Habitat. Central Pacific, Station 266, depth 2750 fathoms. 



Subfamily STAURACONTIDA, S Haeckel, 1881, Prodromus, p. 52. 

 Definition, S taurosphaerida with three concentric spherical lattice-shells. 



Genus 67. Stauracontium, 3 Haeckel, 1881, Prodromus, p. 452. 



Definition. S taurosphserida with three concentric lattice-spheres and four 

 crossed, equal, simple spines. 



The genus Stauracontium differs from its probable ancestral form, Staurolonche, in 

 the duplication of the cortical shell. 



Subgenus 1. Stauracontarium, Haeckel. 



Definition. Pores of the cortical shell regular, all of nearly equal size and similar 

 form ; surface smooth. 



1 Stauro-xiplios = Sword with cross ; <nav^o;, Zi'Qos. 



2 Stauracontida = Staurosphoerida triplicia = Triosphcerida tetracantha. 

 1 Stauracontium = Crossed dart ; <rrai/o'j, *O'J/T. 



