REPORT ON THE RADIOLARIA. 191 



I 



3. Hexaloncharium hystricinum, n. sp. 



Cortical shell spherical, three times as broad as the medullary shell, and densely covered with 

 oblique bristle-shaped by-spines. Pores irregular roundish. Two opposite major spines three-sided 

 prismatic, longer than the shell diameter ; four minor spines pyramidal, scarcely half as long as 

 the shell radius. (Somewhat similar to Hexalonehe hystricina, but distinct in the prolongation of 

 two major spines.) 



Dimensions. Diameter of the outer shell 015, inner O05 ; length of the two major spines 0'2, 

 four minor 0'03, basal breadth 0'02. 



Habitat. South Pacific, Station 288, surface. 



Genus 78. Hexalonchidium^ Haeckel, 1881, Prodromus, p. 451. 



Definition. C ubosphserida with two concentric lattice-spheres and six simple 

 spines of different sizes in pairs ; the two opposite spines of each pair equal, the three 

 pairs unequal. 



The genus Hexalonchidium exhibits the same relation to Hexalonehe that Hexa- 

 stylidium bears to Hexastylus ; the growth of the three spine-pairs is different, whilst 

 both spines of each pair are equal ; they correspond therefore to the three axes of a 

 rhombic crystal. 



1. Hexalonchidium axonometrum, n. sp. 



Cortical shell thin walled, covered with short bristle-shaped by-spines, twice as broad as the 

 medullary shell ; both with regular hexagonal meshes, twice to three times as broad as the bars (inner 

 meshes half as broad as the outer). All three spine-pairs three-sided prismatic, of very different 

 length but of equal breadth (equal to three pores). Major spine-pair twice as long as the shell 

 diameter ; middle pair about equal to the latter, minor scarcely half as long. (Similar to Hexalonehe 

 anaximandri, PI. 22, fig. 5, but distinct in the different length of the spines.) 



Dimensions. Diameter of the outer shell 012, inner 0'06 ; length of the major spines 0'25, 

 middle 01, minor 0'04. 



Habitat. Indian Ocean, Madagascar, surface, Eabbe. 



Subfamily HEXACONTiDA, 2 Haeckel, 1881, Prodromus, pp. 449, 452. 



Definition. C ubosphserida with three concentric, spherical, or octahedral 

 lattice-shells. 



1 Hexalonchidium = Shell with six spears; derivation from Hexalonche. 



2 Hexacontida = Ciibosphaerida triplicia = Triosphserida hexacantha. 



