Palaeozoic Arachnida of North America. 



75 



long. Eyes absent. Of the three free thoracic segments the ante- 

 rior one the shortest. Abdomen oval, broader behind than in front, 

 anteriorly truncated, poste- 

 riorly rounded. It seems 

 probable that the curved 

 lines belong to the ventral 

 surface and if the straight 

 lines alone are counted, 

 then the abdomen was 

 composed of seven seg- 

 ments only. The pedipalpi 

 both visible, the right one 

 showingevensegmentation. 

 They are heavier than the 

 legs and about 22 mm. 

 long, their joints subequal 

 in length with exception 

 of the terminal joint, which 

 is quite small, semilunar. 

 Of the remaining appen- 

 dages only fragments are 

 preserved. The second pair 

 of legs is considerably thin- 

 ner than the others, the ^^^' ^'^' 

 third leg was probably the Figure ^o.-Pvotosolpuga carbonaria n. sp., 

 shortest if judged by the ^olotype, Peabody Mus. No. 155, dorsal sur- 

 comparative shortness of ^^'^^- ^ y 

 its femur. 



Found in the Pennsylvanic (Lower Allegheny) of Mazon Creek, 

 Illinois. 



ORDER RICINULEI 



Arachnids with hard, granulated integument, with a plate or 

 cucullus in front of the cephalothorax and a broad abdomen com- 

 posed of nine segments with a pedicel and coupled to the cephalothorax 

 by means of a special apparatus. Of the abdominal tergites the 

 third to sixth are by far the largest, usually divided into three areas. 

 The first tergite, or pedicel, and the second tergite are not visible 

 when the abdomen occupies its normal position. The seventh to 

 ninth segments are very small, annular, and form a " tail ". Of 

 the sternites the first and second are small, semilunar, seldom visible 



