336 THE VOYAGE OF H.M.S. CHALLENGER. 



the bars. Network of tlie inner cortical shell regular, with circular, hexagoually-framed pores, 

 twice as broad as the bars. From every corner of the hexagons (between three pores) arises a very 

 tliin, hair-like, short radial spiuule. These spinules communicate with one another liy tangential 

 branches (at equal distances fi-om the inner cortical shell), and form thereby an outer, delicate 

 cortical network, with large polygonal meshes and very thin bars. Polar spines very strong, 

 pyramidal, with prominent edges, as long as the main radius of the cortical shell, and half as broad 

 at the base. 



I)imcnsio7is.—M&m axes of the four shells— (A) 0-02, (B) 0-OG, (C) 0-2, (D) 0-22 ; equatorial 

 axes of them — (A) 0-02, (B) 0-06, (C) 013, (D) Olo ; pores of the four shells — (A) 0-002, (B) 

 0-004, (C) 0-008, (D) 0-02 ; bars O'OOl to 0-003 ; length of the polar spines 0-1, basal breadth 0-05. 



Habitat. — South Atlantic, Station 335, depth 1425 fathoms. 



Subgenus 2. Cart/atractus, Haeckel. 



Definition. — Shell composed of two medullary shells and three or more cortical 

 shells. 



4. Cromi/atractus cepiciu.'^, n. sp. (PL 15, fig. 3). 



Caryostijlus cepiciuf, Haeckel, 1879, Atlas (pi. xv. tig. 3). 

 Caryodoras cepiciutf, Haeckel, 1881, Prodromus, p. 454. 



I'roportion of the main axes of the live concentric shells about = 1:2:5:7:8. Network of 

 both spherical medullary shells regular, with small circular pores, about as broad as the bars. Net- 

 work of the three ellipsoidal cortical shells irregular, with large polygonal meshes, five to ten times 

 as broad as the thin bars. Surface of the outermost shell smooth. Polar spines cylindrical, thorny, 

 about as thick as the innermost shell and as long as the outermost shell, against the apex with a 

 spindle-like intumescence, formed by delicate spongy framework (fig. 3). 



Dimensions. — Main axes of the five concentric shells — (A) 0-03, (B) 0-05, (C) 0-16, (D) 0-2, 

 (E) 0-25; equatorial axes of them— (A) O'OS, (B) 0-05, (C) 0-12, (D) 0-16, (E) 0-2; pores of the 

 two medullary shells 0-002 to 0-004, of the three cortical shells 0-02 to 0-04, bars 0-002; length of 

 the polar spines 0-3, breadth 0-03. 



Habitat. — Pacific, central area. Station 268, depth 2900 fathoms. 



5. Cromyatractus ccparius, n. sp. (PI. 15, fig. 4). 



CaryostyliLS ceparim, Haeckel, 1881, Prodromus et Atlas (pi. xv. tig. 4). 



Proportion of the main axes of the .six concentric shells about = 1 : 2 : 7 : 10 : 13 : 18. Net- 

 work of the three inner shells regular, with small, circular pores, which are about as broad as the 

 bars and in the third shell hexagonally framed. Network of the three outer shells irregular, with 

 large polygonal meshes, six to twelve times as broad as the bars. Surface smooth. Polar spines 

 strong, spindle-shaped, thorny, outside of the sixth shell about as long as inside of it; Ijroader than 



