152 



THE VOYAGE OF H.M.S. CHALLENGER. 



I. Subfamily 



Staurostylida. 

 (Shell one single lattice-sphere.) 



Synopsis of the Genera of Staurosphcerida. 

 All four spines equal, 

 Four spines different in pairs, 



II. Subfamily 



Staurolonchida. 

 (Shell with two concentric lattice-spheres. ) 



III. Subfamily 



Stauracontida. 

 (Shell with three concentric spheres. ) 



IV. Subfamily 



Staurocromyida. 

 (Shell with four concentric spheres. ) 



V. Subfamily 



Staurocaryida. 

 (Shell with five or more concentric spheres. ) 



VI. Subfamily 



Staurodorida. 



(Shell a spongy sphere.) 



One spine larger than the three 

 others, ..... 



f 



.e, 



All four spines ( Sim P L 



e( * ua1 ' ( Branched, . . 



Four spines different in pairs, 



One spine larger than the three 

 others, ..... 



All four spines equal, simple, . 



{ All four spines J 



I e 1 ua1 ' (Branched,. 



All four spines equal, 



Solid spongy sphere without medul- 

 lary shell, ..... 



60. Staurosphaera. 



61. Staurostyhis. 



62. Stylostaurus. 



63. Staurolonelie. 



64. Staurancistra. 



65. Staurolonchidiuni. 



66. Stauroxiplws. 



67. Stauraeontium. 



68. Staurocromyum. 



69. Cromyostaurus. 



70. Staurocaryum. 



71. Staurodoras. 



Subfamily SxAUKOSTYLiDA, 1 Haeekel, Prodromus, 1881, pp. 449, 450. 

 Definition. S taurosphserida with one single spherical lattice-shell. 



Genus 60. Staurosphcera, 2 Haeekel, 1881, Prodromus, p. 450. 



Definition. S taurosphserida with a single lattice-sphere and four crossed 

 equal spines. 



The genus Stcmrosphcera maybe regarded as the common ancestral form of this sub- 

 family, since it represents their most simple and primitive form. From the surface 

 of the simple lattice-sphere, enclosing the central capsule, arise four equal, simple, radial 

 spines, opposite in pairs in two diameters, perpendicular one to another. Staurosphcera 

 may be derived phylogenetically either from Cenospliwra by production of the four 

 spines, or from Hexastylus by reduction of two opposite spines. 



1 Staurostylida Staurospliserida simplicia = Monospliocrida tetracantha. 



2 Staurosphcera = Cross-sphere ; m-at/jo'? 



