LIFE IN THE PAST 171 



nal sea which spread over what is now known as the 

 Mississippi Valley. Everywhere over this region must 

 have grown in the shallow water great numbers of 

 creatures called crinoids or stone lilies. They were 

 attached to the bottom by slender stems, sometimes 

 many feet long. These stems are jointed, and when 

 they became fossilized the sections were apt to sepa- 

 rate, with the result that over a wide area in the 

 Mississippi Valley it is very common to find these 

 little segments which look not unlike checkers. At the 

 end of the stem was a rounded head, with a mouth 

 at the top, and around the mouth were branched, 

 feathery arms. The creatures must have been ex- 

 quisitely beautiful, but they have completely disap- 

 peared from the face of the earth, with the exception 

 of a very few, found in the obscurity of the almost 

 fathomless depths of the great ocean. Here they 

 remain as peculiar relics, only preserved by the un- 

 varying conditions in the deep sea from the extinc- 

 tion that has met their sisters. 



Those who are familiar with our seacoast will know 

 an interesting creature known as the horseshoe crab, 

 or king crab, though in reality it is not a crab at all. 

 It is rather more nearly related to the spiders than 

 the crabs, though no one but a technical zoologist 

 could possibly associate them together. The ancestors 

 of these king crabs were the finest and best developed 



