Palaeozoic Ayachnida of North America. 



43 



segment, 21.0 mm. Length of the four preserved post-abdominal 

 segments, 23.0 mm. 



Length of pedipalp : femur. 6,3 mm., patella, 6.3 mm., tibia with 

 finger 11. 7 mm. 



All four specimens are from the Pennsylvanic (Lower Allegheny) 

 of Mazon Creek, Illinois. 



Eoscorpius danielsi n. sp. 

 Plate IV, fig. 16; text fig. 8. 

 The reverse of the nodule containing the type specimen is not in 

 existence. The obverse is in the collection of Mr. L. E. Daniels. 



Figure 8.— Eoscorpius danielsi n. sp., holotype, Daniels coll. X y- 



It is a badly deformed specimen without palpi and cauda and with the 

 legs torn from the body and intercrossing each other to such an extent 

 that it is impossible to decide to which each remnant belongs. 



The cephalothorax is preserved better than the rest, and is 11 mm. 

 long and 14 mm. wide at the posterior edge, which is slightly recurved. 

 Anteriorly the cephalothorax is somewhat narrower, the width in 

 the region of the alveolate areas being 10 mm. The anterior and the 

 side edges are straight, the angles rounded. A curved ridge runs on 

 each side close to the alveolate region, from the anterior edge back- 

 ward, gradually becoming lower and changing into a shallow sulcus, 



