Palaeozoic Arachnida of North America. Ill 



num oval. In front of it two heavy chelicera, evidently bent down- 

 ward, so that their distal end reaches the sternum. At the sides of the 

 chelicera are the coxae of the pedipalpi. The coxae of the legs are 

 radiating from the sternum. The fourth coxae are fully twice as 

 long as the first. All trochanters are one-jointed. Of the legs arc 

 preserved only the femora of the second right and fourth left leg. 

 They are very long and slender and from their appearance it is prob- 



Fig. 68. Fig. Og, 



Figure 6S. — Protopilio longipes n. sp., holotype, Peabody Mus. No. 171, 



ventral surface. Figure 69. — Pro/o/'z/io depressiis n. sp., holotype. U. S. N. M. 



No. 37974, ventral surface. X y 



able that all legs were long and slender. The whole body is quite 

 flat. Total size with chelicera 10.5 mm. 



Found in the Pennsylvanic (Lower Allegheny) of Mazon Creek 

 Illinois. 



Protopilio depressiis n. sp. 

 Plate X, fig. 56; text fig. 69. 

 A very imperfectly preserved specimen in the U. S. National 

 Museum under No. 37 974. The nodule presents both the obverse and 

 reverse, but the detail of the structures cannot be seen. Abdomen 

 chipped off at its extreme end. Probable length of the body 24.5 mm. 

 Width of abdomen on the level of the posterior edge of the second 

 sternite lo.o mm. In the anterior part of the abdomen several heavy 

 transverse folds which make the counting of sternites in this region 

 very uncertain. Beginning with the fourth sternite represented in 



