122 



THE VOYAGE OF H.M.S. CHALLENGER. 



I. Subfamily 



Xiphostj'lida. 

 (Spherical shell simple. ) 



II. Subfamily 



Sphserostylida. 

 (Two concentric spheres.) 



III. Subfamily 



Amphistylida. 

 (Three concentric spheres.' 



TV. Subfamily 



Cromyostylida. 

 (Four concentric spheres.) 



V. Subfamily 



Caryostylida. 



(Five or more concentric 



spheres. ) 



VI. Subfamily 



Spongostylida. 

 (Spherical shell p;utially or 

 wholly of a spongy structure. ) 



Synopsis of the Genera of StijlosphcBrkla. 



( Polar spines free, without f Both spines equal, 

 I connecting ring on the ' 



distal ends. 



i 



Spines different in size 



] [ or form, . 



[ Both polar spines united by a circular or elliptical ring, 



f Both spines equal, 



Polar spines free. 



i 



Spines different in size 



opine* tLiiicie 



[ or form, 



Both polar spines united by a circular or elliptical ring, 



Both spines equal, 



Polar spines free. 



Spines different in size 

 or form, 



Both polar spines united by a circular or elliptical ring, 



Both spines equal. 

 Spines different, . 



Polar spines free. 



Polar spines free. 



Both spines equal. 



C Shell a solid spongy sphere without central medullary 

 1 shell, 



[ One central medullary 

 In the centre of the spongy j shell, 

 sphere one or two medul- -{ 

 lary shells. i Two concentric medul- 



[ lary shells. 



45. Xiplwsphcera. 



46. Xiphostylus. 



47. Saturnalia. 



48. Sti/losj)hcera. 



49. Splicerostylus. 



50. Saturnulus. 



51. Amjihisphaira. 



52. Ampldstylus. 



53. Satuniinus. 



54. Stijlocromijum. 



55. Cromyostylua. 



56. Caryostylus. 



57. Sponyolonclie. 



58. Spongostybis. 



59. Sponfjostylidium. 



Subfamily Xiphostylida, Haeekel, 1881, Prodromus, pp. 449, 450. 

 Definition. — S t y 1 o s p li a3 r i d a with one simple spherical lattice-.shell. 



Gemis 45. Xiphosphcera,^ Haeekel 1881, Prodromus, p. 450. 



Definition. — S t y 1 o s ph a3 r id a with cue single lattice-sphere and two free 

 spines of equal size and form. 



The genus Xiphospliara is the most simple form of all Stylosphserida, and may 

 be regarded as the common ancestral form of this family. On the surface of a simple 



1 A'i/j7iOsjj/if(.'ra = Sword-sphere ; l/ipoj, a^aJja. 



