45 



On tin- rt.ntr.iry, it seems that living objects show a certain 



2v 

 n nee for symmetry-axes of a period of . 



-Dim- interesting examples of this kind, we may mention the 



Fig. 46. 

 Circoporus octahedrus. 



Fig. 47- 

 Circorhegma dodecahedra. 



Dlendid forms of some radiolaries (Phaeodaria): of Circoporus octa- 

 irus (fig. 46), of Circorhegma dodecahedra (fig. 47), and of Circo- 

 lia icosahedra (fig. 48), all according to Haeckel's original de- 

 scriptions ; they are very striking instances of the symmetry of the 

 )ups K and P respectively, and these animals manifest in a most 

 mvincing way their morphological relations to the regular endo- 

 )herical polyhedra, and more 

 2cially to the octahedron, the 

 mtagonal dodecahedron, and 

 le icosahedron. 



As further instances of the 

 )up K we may mention from 

 same family of creatures: 

 \ctinomma drymodes, and Aste- 

 racanthion, after Haeckel's des- 

 criptions; of the group P\ Aulo- 

 sphaera icosahedra in its youth- 

 forms; etc. 



In the vegetable world a 

 certain number of pollen-cells 



M ( in to belong to these symme- 



Fig. 48. 

 Circogonia icosahedra. 



