A CERA TA—ARA CHNIDA . 



415 



lonethi, Tertiary and Recent). An example of the first order is 

 Ixodes tertiarius Scudder of the OHgocenic Green River beds of 

 Wyoming, the other is unknown in America. In the Carbonic order 



Fig. 1 716. Arthrolycosa aniiqua. Nat. size. ( After Beecher. ) 



Anthracomarti the cephalothorax and abdomen are distinct, the lat- 

 ter being segmented. {Examples: Arthrolycosa antiqua Harger 

 (Fig. 1716) ; Geraphrynus carbonarius Scudder; Architarbus ro- 

 tundatus Scudder, and Anthracomartus pustulatus Scudder of the 

 Coal Measures of Mazon Creek, Illinois, and A. trilobitus Scudder 

 (Fig. 1717a) of the Fayetteville shale of Arkansas. In the order 

 Pedipalpi, the cephalothorax and abdomen are distinct, the latter 

 is segmented and sometimes continued in a slender postabdomen; 



Fig. 



[717. a, Anthracomartus trilobitus, Xf I 

 Scudder. ) 



b, Geralinura carbonaria. ( After 



the first pair of legs are exceptionally long. They range from 

 the Devonic to the Present. Examples: Geralinura carbonaria 



Scudder (Fig. lyiyh) of the Coal Measures of Mazon Creek, 



