CARBONIFEROUS ARACHNIDA OF NORTH AMERICA. 455 



margin, the sides well rounded, the whole not more than half as large as the abdomen, 

 which is cylindrical, perhaps depressed, and composed of nine principal joints, of which 

 the first thi-ee are a little shorter than the others, followed by a post-abdomen of three 

 much contracted joints, and this by the jointed thread peculiar to the family, and Avhich 

 is as long as the al)domen. A pair of eyes oa the front of the cephalothorax. Palpi large, 

 robust, composed of three similar joints, spinous within, and the apical coarsely chelate. 

 First pair of legs thread-like, no stouter than the tail, and longer than it; second and 

 third pairs of legs moderately slender, eqnal, the last pair similar but considerably longer, 

 supported by a transverse independent joint between the cephalothorax and abdomen. 



This genus, fli'st described in Jnne, 1884, was brought to the attention of the Ameri- 

 can Academy only nine days before another species of the same genus was desci'ibed by 

 KuSta to the Bohemian Academy; a fact the more striking since up to that time no 

 Pedipalpi had ever been found fossil even in tertiary or secondary rocks, unless credit 

 be given to Sei-res' mention of a species in the tertiary marnes of Aix. Ivusta has since 

 described several species from the Bohemian coal. 



Geralinura carbonaria. 



PI. 39, figs. 1, 3, 4. 



Geralinura carhonaria Scudd., Proc. Amer. Acad. Arts Sc, xx, 19-20 (1884). 



Cephalothorax broadest in the middle, but tapering more i-apidly in front than poste- 

 riorly, the front triangularly produced but the extreme tip rounded; apparently a pair of 

 globular eyes are situated in front as in G. hohemica, but larger, notwithstanding that 

 they are seated on a much narrower spot. The front pair of legs are of the same size as 

 the tail ; the second pair have the femur hardly half so stout as that of the hind pair, which 

 is nearly as broad as one of the middle abdominal joints, that of the middle pair ap- 

 proaching the former rather than the latter. The abdomen is regulai'ly obovate, twice 

 as long as the thorax even excluding the post-abdomen, and half as broad again as that. 

 The post-abdomen composed first of two joints, together half as long as broad and one- 

 third as broad as the abdomen, next of a single quadrate joint, followed by the thread 

 which is about one-fourth or one-fifth as broad as the tip of the post-abdomen, and about 

 as long as the body, composed of numerous joints, as far as can be seen about twice as 

 long as broad. In one of the two specimens found, the body is piceous fi-om carbona- 

 ceous matter, but interi-upted at the abdominal interstices and traversed irregularly by 

 broken, longitudinal, slenderer interruptions of the color of the stone. 



Length of body to base of tail (a), 16 mm.; (b), 13 mm.; of tail (a, broken), 4 mm., 

 (&, probably perfect), 12 mm.; of cephalothorax («),4 mm.; postthoracic plate («), 0.75 

 mm.; abdomen (a), 8.5 mm.; postabdomen (a), 2.5 mm.; breadth of cephalothorax (a), 

 2.6 mm.; postthoracic plate (a), 1.75 mm.; abdomen (a), 4.5 mm.; postabdomen («), 1.4 

 mm. ; thread (a) , 0.25 mm. ; breadth of first pair of legs («) , 0.25 mm. ; second paii" (a) , 0.5 

 mm. ; third pair (a), 0.75 mm. ; fourth pair (a),l nun.; length of femora of third pair (a), 3.5 

 mm.; of fourth pair (o), 5 nun. 



Mazon Creek, 111. Mr. R. D. Lacoe, two specimens, Nos. 1754a-d. 



The species diffei-s considerably from G. hohemica Kusta sp., first in its much smaller 

 size, then in its much more pointed and ovate cephalothorax. It would appear indeed 



