ECHINIDEA. 507 



That Omnipotent Creator, infinite in His resources who, 

 in at least the details of His workings, seems never yet to 

 have repeated Himself, but, as Lyell well expresses it, 

 breaks, when the parents of a species have been moulded, 

 the dye in which they were cast, manifests Himself, in 

 these four great ideas, as the unchanging and unchangeable 



Fig. 242. HolotTiuridea, Sea-cucumbers. 



One. They serve to bind together the present with the 

 past, and determine the unity of the authorship of a wonder- 



