19« THF-: VOVAUE OF II.. M.S. rHAl,r.i;X(iKi:. 



20. II('.f<ii-(,}iflii ni (//<nJ/iifi/in. 11. sp. (PI. 25, fio-. 8). 



Cortical .'^hcll \erv lliic-k walled, .spiny, with irregular network ; it.'; meshes rnuiiilisli, twn 

 to fi\e times as broad as the bars, of very ditlerent size, ten to fifteen on the half 

 meridian. Bars between them very strong, thi-ee-sided prismatic, armed with a gr-eat nnmber 

 of .small thorns, and with larger spines at the nodal-points between every three meshes. 

 Radial proportion of the three spheres = 1 : o : 12. Six .strong radial main spines three- 

 sided prismatic, with three prominent, somewhat contorted wings, acute, broader than the 

 diameter of the inner shell and as long as the diameter of the outer shell. These six 

 main spines are situated in the same three dimensive axes as the six thin radial beams 

 connecting the two medullary shells. But the six radial beams which connect the middle with 

 the outer shell alternate with the former and lie in three other dimensive axes, — a very 

 rare and remarkable disposition. 



Dimensions. — Diameter of the outer shell t>2, middle 0'05, inner O'OIG ; cortical pores O'Ol to 

 0-0?., bars 0-006 ; length of the six spines 0-2, breadth 0-02 to O'OS. 



Habitat. — Tropical Atlantic, Station ?A2, depth 1445 fathoms, 



21. Hexacontitim ■'^etosion, ii. sp. 



Cortical shell thin walled, covered with numerous bristle-shaped, simple, radial by-spines of 

 variable length. Pores irregular roundish, five to seven on the radius, two to eight times 

 as broad as the bars. Radial proportion of the three spheres = 1 : 3 : 9. Main spines three- 

 sided pyramidal, as long as the radius. 



Dimensions. — Diameter of the outer shell O'l to (i'15, middle (rt):',.^ to O'Ou, inner 0'01."'i to 

 0-010 ; cortical pores 0-01 to O'O?., bars O-OOM to 0-004 ; length of the six spines 0-0." to 0-08, 

 basal breadth 0-012 to 0-015. 



Habitat. — Cosmopolitan ; jMediterranean, Atlantic, Pacific, surface ; also fossil in Barbados. 



22. Hejcaront III m furcation, n, sp. 



Cortical shell tliin walled, covered with uumer(jus thin, bristle-shaped by-spines, whicli are 

 forked and nearly as long as the main spines. Pores irregular roundish, eight to ten on 

 the radius, two to eight times as broad as the bars. Radial proportion of the three 

 s])heres = l : 2-5 : 10. Main spines triangular pyramidal, .shorter than the radius. 



Dimensions. — Diameter of the outer .shell 0-1 S, niiildle 0-045, inner 0-(il8-. cortical pores 0-005 

 to 0-015, bars 0-002; length of the six sj.ines 0-07, basal breadth 0-015. 



Habitat. — Xorth Atlantic, Station 354. surface. 



2:1. Hexacontiinn dri/modcf, Haeekel. 



ArtiiKimma dnjmiidi'fi, Haeckel, 18G2, ]Monogr. d. Radiol., p. 442, Taf. xxiv. fig. 9. 



Cortical shell thin walled, covered with numerous thin, bristle-slui))ed spines, which are double 

 forked ami half as long as the main spines. Pores irregular roundish, eight to ten on the radius, 



