4i6 



NORTH AMERICAN INDEX FOSSILS. 



y 



Illinois. The scorpions (Scorpiones) have the abdomen of two 

 parts, a preabdomen of seven broad segments and a postabdomen 

 of six long slender segments, the last of which forms a hollow 

 spine or sting. Proscorpius osborni Whitfield has been considered 

 the oldest American scorpion — occurring with the Eurypterids 



Fig. 171 



Eoscorpius carbonarius. A, natural size; B^ comb (pecten), enlarged; 

 C, body segment, enlarged. (After Meek & Worthen. ) 



in the Bertie waterlimes of New York. Eoscorpius carbonarius 

 Meek and Worthen (Fig. 1718) and E. (Mazonia) woodanus 

 M. & W. from the Coal Measures of Illinois are American Car- 

 bonic species. The false spiders, of the order Opiliones (unknown 

 in American deposits), have cephalothorax and abdomen fused, 

 whereas they are distinct in the true spiders or Araneco. The > 

 latter go back to the Carbonic, but are more characteristic of the 

 Tertiary. Parattus evocatus Scudder, P. latitatus Scudder and 

 P. resurrectus Scudder and Titanoeca hesterna, T. ingenua Scud- 

 der, and Linyphia retensa Scudder, Tethnaeus hentzii Scudder, 

 etc., and Epeira abscondita Scudder, etc., from the Oligocenic 

 beds of Florissant, Colorado, are American examples. 



