86 THE VOYAGE OF H.M.S. CHALLENGED 



Genus 24. Caryosphcera, 1 Haeckel, 1881, Prodromus, p. 454. 



Definition. L iosphserida with two intracapsular (medullary) shells and three 

 or more extracapsular (cortical) shells ; the former united with the latter by radial 

 beams piercing the wall of the central capsule. 



The genus Caryosphcera, the only observed form of this subfamily, comprises 

 those Liosphserida in which the shell is composed of two medullary and three 

 or more cortical shells. Such forms (without radial spines) are very rare ; I 

 observed only two species, one with five, the other with six shells. They are 

 derived from Cromyosphcera by further apposition of outer cortical shells. 



1. Caryosphcera pentalepas, n. sp. 



Shell composed of five concentric spheres, with the radial proportion = 1:2:8:10:12. Both 

 medullary shells with regular circular pores, twice as broad as the bars. First cortical shell with 

 regular, circular, hexagonally framed pores, three times as broad as the bars ; second cortical shell 

 with regular hexagonal pores, four times as broad as the bars ; third (outermost) cortical shell with 

 regular hexagonal pores and very thin thread-like bars. Surface smooth. 



Dimensions. Diameter of the five shells (A) 0'02, (B) 0'04, (C) 016, (D) 0'2, (E) 0'24. 



Habitat. Central Pacific, Station 274, depth 2750 fathoms. 



2. Caryosphcera hexalepas, n. sp. 



Shell composed of six concentric spheres, with the radial proportion = 1:2:4:5:6:8. All six 

 shells with regular circular pores, two to four times as broad as the bars, with increasing size from 

 the centrum against the smooth surface. 



Dimensions. Diameter of the six shells (A) 0'025, (B) 0'05, (C) 01, (D) 013, (E) 016, (F) 0'2. 



Habitat. Central Pacific, Station 268, depth 2900 fathoms ; also fossil in Barbados. 



Subfamily PLEGMOSPH^RIDA, 2 Haeckel, 1881, Prodromus, p. 455. 



Definition. L iosphaerida with spongy spherical shell, with or without 

 latticed medullary shell in the centre. 







Genus 25. Styptosphcera, 3 Haeckel, 1881, Prodromus, p. 455. 



Definition. L iosphserida forming a solid sphere of spongy framework, without 

 enclosed medullary shell, and without central cavity. 



1 Caryosphcera = Nut-sphere ; xaji/oi/, a$aii%a,. 



2 Plegmosphaerida = Liosph8erida spongiosa = Spongosphaerida anacantha. 



3 Styptosphcera = Hemp-sphere ; OTVTTTO;, 



