16 TERRESTRIAL CARBONIFEROUS ARACHNIDA. 



are wonderfully well preserved. The tergum bears many scattered coarse granules, 

 has coarsely granular lateral margins, and a pair of coarsely granular longitudinal 

 keels lying slightly obliquely, each keel being rather nearer to the lateral edge than 

 to its fellow of the opposite side ; the sternum, on the other hand, is smooth 

 except for two coarsely granular longitudinal keels, one on each side of the middle 

 line. The sterna in front of this are not sufficiently well preserved for me to state 

 definitely that they were laminate and lobate posteriorly as in Mr. Holt's 

 specimen, but there are indications that this was so. 



Measurements in mm. — Total length of abdominal portion of opisthosoma 

 (contracted) 28 ; width of the same (distended) 22 ; width of tergum of the last 

 segment 17, of sternum 20; length of femur of fourth leg 13, of patella 11, of 

 tibia 11. 



According to Fritsch's restoration, the type of Isobuthus, I. kralupensis, Thorell 

 and Lindstrom, resembles Eobuthus raJcovnicensis in the mode of attachment of the 

 coxse of the legs of the third and fourth pairs to the body. It also appears to have 

 the posterior margin of the sterna of the fourth, fifth and sixth segments of the 

 opisthosoma bilobate and mesially notched, as in Mr. Holt's specimen described 

 above. On the evidence, therefore, Isobuthus must be assigned to the same group 

 of Scorpions as Eobuthus; but according to the figures published by Fritsch, 

 Isobuthus has tolerably normal chelas with the movable finger greatly exceeding in 

 length both the length and breadth of the hand. Since the chelas are unknown in 

 Mr. Holt's specimen, it is possible that the species it represents may be congeneric 

 with Isobuthus kralupensis. 



Genus PALiEOMACHUS, nov. 



1876. Eoscorpius, H. Woodward (in part), Quart. Journ. Geol. Soc, vol. xxxii, p. 58, pi. ~viii. 



Generic Characters. — Hand broad and oval, its width greatly exceeding that 

 of the brachium, its length exceeding that of the fingers, which are short and in 

 contact when closed, the length of the immovable digit about equal to the width 

 of the hand. Caudal segments short and stout, apparently about as long as they 

 are wide or high, and not progressively increasing in length from the base to the 

 tip of the tail. 



Type Species. — Eoscorpius anglicus, H. Woodward. 



Palaeomachus anglicus (H. Woodward). Text-figure 2. 



1876. Eoscorpius anglicus, H. Woodward, Quart. Journ. Geo]. Soc, vol. xxxii, p. 58, pi. viii, fig. 3 

 (type), also i gs. 1 and 2. 



The type species of this genus was based upon three specimens, namely, the 

 extremity of a chela from Mansfield in Nottinghamshire, five caudal segments 



