66 THE HISTORY OF CREATION. 
cases the whole skeleton consists of only one flinty star, and 
is then generally composed of twenty staves, distributed 
according to definite mathematical laws, and united in a 
Fic. 16.—Cyrtidosphera echinoides, 400 times enlarged. c. Globular 
central capsule. s. Basket-work of the perforated flinty shell. a. Radial 
spikes, which radiate from the latter. p. The pseudo-feet radiating from 
the mucous covering surrounding the central capsule. l. Yellow globular 
cells, scattered between the latter, containing grains of starch. 
common central point. The skeletons of other Radiolaria 
again form symmetrical m any-chambered structures, as in 
the case of the Polythalamia. Perhaps no other group of 
