EEPOET ON THE EADIOLARIA. 203 



1. Ciibosphcera cuhaxonia, u. sp. (PL 24, fig. 8). 



Hexacromijon cubaxonium, Haeckel, 1881, Prodrom. et Atlas. 



Shell composed of five concentric spheres, with the radial proportion = 1 : 3 : 8 : 10 : 1.3. Tlie two 

 medullary shells with small regular, circular pores of the same breadth as the bars. Inner cortical 

 shell (third shell) with large regular, circular pores, four times as broad as the bars, hexagonally 

 framed. From each hexagon-corner arises a thin bristle-shajjed radial by-spine, which at a fixed 

 distance from the centre is united with the middle cortical shell (fourth shell), which ha.s very small 

 circular pores. The beginning of the fiftli shell (outermost) is indicated by six small reticula, 

 produced by the six main spines at equal distances from the centre. All five shells are united by 

 six prismatic radial beams, ending outside in pyramidal furrowed spines. 



DiTnensions.—QiKmQiex of the five shells— (A) Q% (B) OlS, (C) 012, (D) 0-045, (E) 0-015. 



Hahitat. — Central Pacific, Station 2V2, depth 2600 fathoms. 



2. Cahosphcera concentrica, n. sp. 



Shell composed of six concentric spheres, with the radial proportion= 1 :2 : 6 : 7-5 : 9 : 11. 

 The two medullary shells with regular, circular pores, twice as broad as the bars. The four cortical 

 shells of the same structure, with irregular, roundish pores, three to four times as broad as the bars. 

 The size of these pores and the breadth of their bars gradually increase towards the smooth surface. 

 All six shells are connected by six thin three-sided prismatic radial beams, which are prolonged 

 outside in six stronger spines, angular pyramidal, with smooth edges, as long as the shell radius. 



Di7ne?isions.—Dmmetev of the six .shells— (A) 0-2, (B) 0-4, (C) 0-12, (D) 0-15, (E) 0-18, (F) 0-22. 



Hahitat. — Central Pacific, Station 268, depth 2900 fathoms. 



Gen-US 84. Hexacaryum} Haeckel, 1881, Prodromus, p. 454. 



Definition. — Cub o sp li ser id a with five to six or more concentric lattice-shells 

 aod six branched spines of equal size. 



The genus Hexacaryum is distinguished fi-om the foregoing Cnhosphasra hy 

 ramification of the six radial spines, and therefore exhibits the same relation to it that 

 Hexancistra bears to Hexastylus, &c. 



1. Hexacaryum arhorescens, n. sp. (PI. 23, figs. 4, 4a). 



Shell composed of five, six, or more concentric shells, which are united by six very large 

 radial spines. The two medullary shells spherical, inner with regular, circular, outer with irregular 

 polygonal pores. All cortical shells (third and following) not spherical, but regular octahedral, with 

 irregular polygonal meshes and thin bars. Eadial spines prismatic, with three wing-lLke, spirally 

 twisted edges, which at equal distances send out thin forked lateral branches (six on each 



' Hexacaryum = Yi'at with six spines ; t|a, xa^vov. 



