ECHINODERMATA. 65 



creatures of this description as a corn-field is with 

 corn. Many large kinds are found in a fossil state 

 in our chalk and limestone rocks, and vast strata 

 of marble, extending over large tracts of country in 

 Northern Europe and in North America, are entirely 

 made up of their petrified skeletons. 



u Man applies it to construct his palace and adorn 

 his sepulchre; but there are few who know, and fewer 

 still who appreciate, the surprising fact that much of 

 this marble is composed of millions of the skeletons 

 of organized beings, once endowed with life, and 

 susceptible of enjoyment, which after performing the 

 part that was for a while assigned to them in living 

 Nature, have contributed their remains towards the 

 composition of the mountain masses of the earth." 

 DR. BUCKLAND. 



The numerous pieces of which their stems were 

 formed are met with in abundance in the north of 

 England, where they are popularly known as St. 

 Cuthbert's beads, while their polype-like heads have 

 been regarded as petrified flowers, and designated 

 " Lily stones " (Fig. 43). The origin of these beau- 

 tiful fossils, formerly so mysterious, is thus easily 

 explained. 



The Feather-star (Comatula)* (Fig. 44, e), common 

 upon our coast, is but an Encrinite without a stem, and thus 

 enabled to move freely at the bottom of the sea. The central 

 box which contains the stomach is furnished with a mouth, 

 around which radiate the arms, fringed with a double row 

 of jointed filaments ; by means of these the Feather-star 

 can creep upon the sand, or twining them around the stems 

 of sea-weeds or corals, it can climb in search of food, or 

 by the undulations of its feathery filaments, row itself from 

 place to place through the water, with a graceful gliding 

 motion. 



The Sea-baskets (GorgonocepJialus)^ (Fig. 44, 5). In 

 these elaborately- constructed creatures, the shell of the 

 living animal is entirely covered with a thick fleshy crust. 

 From the circumference of the disk proceed five strong rays, 



* Comatus, having hair. 



t ropyw, Gorgon, Medusa ; /cedxxA^, kephale, the head. 



