CARBONIFEROUS ARACHNIDA OF NORTH AMERICA. 453 



though nowhere seen on the stone, appears to be regularly obovate, bi'oadest at or before 

 the middle and much broader than the cephalothorax, with which it ai)pearsto be united 

 thi'oughout the base, the sides of the body showing little excision at their junction. The 

 abdominal segments are equal in length. The entii-e surface of both cephalothorax and 

 abdomen is closely covered with very irregularly polygonal, or rounded subovate, sunken 

 cells of varying size, but generally tolerably large, the largest foiiuing pyriform cells 

 lining internally the abdominal carinae, one to each segment, the broadest end anterior. 

 The legs are moderately stout, very long, thickened at the joints, the fourth pair appar- 

 ently the longest, the first pair comparatively small ; the palpi, as far as they can be 

 seen, aj^parently similar to the front legs but still smaller. 



Length of body, 15 mm.; cei)halothorax, 6 mm.; abdomen, 9 mm.; width of cephalo- 

 thorax iu front, 4 mm., behind, 7 mm.; abdomen, 8 mm.; length of first two joints of first 

 pair of legs, 4.5 mm.; of third pair, 5 mm.; of fourth pair, 5 mm.; first four joints of third 

 pair of legs, 12 mm.; of fourth paii', 13.5 mm.; lengthof second joint of first pair of legs, 

 3 mm.; of same (?) joint of palpi, 1.75 mm. 



Mazon Creek, 111. Collection of Mr. K. D. Lacoe, No. 1752. 



Order PEDIPALPI Latreille. 



Family Geealinukidae Scudder. 



Cephalothorax divided into two masses: the hinder much the smaller, short and trans- 

 verse, and cai-rying only the hindmost legs; the front portion large, tapering anteriorly, 

 and. furnished with long and slender cheliceres. Abdomen subfusiform. While most 

 nearly related to the Thely|>honidae, this family, by the division of the cephalothorax, 

 shows some affinity to the Nyctalopidae. Two genera have been found belonging here. 



Graeophonus gen. nov. (rf"''"', ^^-iv"?). 



Cephalothorax remai-kably short and stout, rounded quadrate (especially rounded in 

 front, nearly quadratiform behind, the sides neai-ly straight, the hinder margin gently 

 convex), divided into radiating pedigerous segments. Palpi very stout, chelate at tip. 

 First pair of legs like the others in all general I'espects, very stout, flattened and taper- 

 ing, of no great length. Abdomen ovate, largest iu the middle, rather narrowly attached 

 at base, composed of twelve similar segments, excepting that the last three rapidly nar- 

 row and are considerably shortei- than the others, but the posterior curve of the alidomen 

 is not interrupted to foi-m a j^ost-abdomen as in other Pedipalpi. Whether an articulated 

 seta follows the last joint cannot be told from the specimen preserved; a pair of distant, 

 distinct, and divergent furrows are seen on the first and second abdominal segments of 

 a cast of one specimen, reaching halfway across the second segment, and occupying the 

 place which the "combs" of modern scorpions occupy. 



This genus pretty plainly falls into the Pedipalpi on account of the stout chelate palpi 

 and the number of abdominal joints; but the absence of a post-abdomen, perhaps also of 

 a seta, the tuiditferentiated character of the first pair of legs and the radiated arrange- 



