328 



THE WONDERS OF GEOLOGY. 



Lect. IV. 



polygonal plates, closely fitted to each other ; and the 

 surface is divided vertically by bands, like the meridians 

 of a globe, having rows of double perforations. The shell 

 is studded over with papillae, which vary in size, in the 

 different species, from mere granular points to large well- 

 defined tubercles. To these papillae, spines are attached, 

 which also present great variety of figure and decoration ;* 

 these are the instruments of motion, and as on the death 



LlGN. 62. — ECHINITES AND SPINES, FROM THE CHALK. 



(Figs. 5, 7, one-third less than the originals.) 



Fig. 1. Cidaris diadema. 2, 4, 9. Spines of Cidaris. 3. Nucleolites. 5. Anan 

 chytes ovatus. 6. A tubercle of a Cidaris. 7. Spatangus cor marinum. 8. Spines 

 and portion of the shell of a Cidaris in flint. 



of the animal, the tendons by which they were fixed to 

 the shell decompose, the rarity of fossil specimens, with 

 these processes attached in their natural position, is readily 

 explained. The Echini, both recent and fossil, comprise a 



* Medals of Creation, vol. i. p. 348. 



