EXTINCT ANIMALS 



ternal skeleton, consisting of carbonate of lime, 

 which was a very prominent feature in their 

 structure. It is of the same nature as the hard 

 box-like skeleton of the sea-urchins, which, with 



Fig. 215. — Photograph of a block of Limestone of the Car- 

 boniferous period from Iowa, United States of America, 

 showing several kinds of Stone-lilies or Encrinites. They 

 are lettered as follows : A. Rhodocrinus kirbyi, W. and Sp. 

 B. Rhodocrinus tvatersianus, W. and Sp. C. Platycrinus 

 'planus, Ow. and Sh. D. Platycrinus symnietricus, W. and 

 Sp. E. Dorycriyius inimaturus, W. and Sp. F. Dicho- 

 crinus inornatus, W, and Sp. (Photograph lent by Dr. 

 Bather). 



the star-fishes, form the great group called by 

 naturalists the Echinoderma. 



In the eighteenth century a specimen of a 

 living Encrinite or stalked star-fish was dis- 

 covered in the deep water off Martinique in the 

 West Indies, and was brought in a dried con- 



288 



