290 



THE VOYAGE OF H.M.S. CHALLENGER. 



The central capsule of the EUipsida is in all cases ellipsoidal, and occupies the 

 largest part of the shell, being separated from its inner surface by a thizrner or thicker 

 jelly-mantle. 



Sy7iopsis of the Genera of EUipsida. 



Ellipsoidal shell without 

 polar appendages (neither 

 solid spines nor hollow - 

 tubes at the poles of the 

 axis). 



Surface without radial 

 spines. 



f Shell cavity simple, without 

 I an axial rod, 



I Shell cavii)" with a trans- 

 [ veiso axial rod, . 



Surface covered with radial spines, 



f Shell cavity airaple, without 

 Solid sj)ines of similar | axial runs, 

 shape, at both poles of -j 



the main axis. j Shell cavity with a cross of 



[ axial rods, 



Ellipsoidal shell with polar 

 appendages (either solid 

 spines or hollow fenes- ■{ 

 tiated tubes) at the poles 

 of the main a.xis. 



Solid spines of different 

 sliape, at both poles of 

 the main axis. 



Two polar spines of 

 different shape, . 



A bunch of spines at one 

 pole only, 



Onlj- a single spine at 

 one pole, 



Two hollow fenestrated tubes opposite, at the poles of the 

 main axis, ...... 



122. Oenellipsis. 



123. AxeUyms. 



124. Kllq>.si(lium. 



125. Ellipsoxiphus. 



126. Axojirunum. 



127. ElJijisosfyhis. 



128. Liihumcttpilus. 



129. Li'/hrqtium. 



130. Pq.Ttidhi. 



Genus 122. Cenellipsis,^ n. gen. 



Definition. — EUipsida with simple ellipsoidal shell, without radial spines and 

 without polar tubes. 



The genus Cenellip>sis is the simplest and most primitive form, not only among the 

 EUipsida, but also among the P r u n o i d e a, and it may therefore be regarded as the 

 common ancestral form of the whole family. It corresponds to Cenosphcera among 

 the S p h 86 r o i d e a, to Cenodiscus among the D i s c o i d e a, to Cenolarcus among 

 the Larcoidea. Probably it is derived from Cenosphcera by prolongation of 

 one axis. 



Subgenus 1. Cenellipsium, Haeckel. 

 Definition. — Network of the shell regular, with meshes of equal size and similar form. 



' CWieHjysts= Hollow ellipsoid ; r.svoi. i'KKif^ii. 



