SCORPIONES. 11 



evidently not sufficiently intimate to inspire confidence in the accuracy of his 

 interpretations of the fossils. This fact, coupled with the imperfect preservation 

 of many specimens, makes the classification of the British species, put forward in 

 the following monograph, provisional in many respects. I hope, at least, that it 

 may help those who come after me to improve upon the system here proposed. 



All the British species of Carboniferous Scorpions hitherto described have 

 been referred to the genus Eoscorpius, Meek and Worthen, which was based upon 

 a single species, E. carbon arms, from Mazon Creek, Illinois (Amer. Journ. Sci., ser. 

 2, vol xlv, 1868, p. 560). The chelae are unknown; but the last tergal plate of 

 the abdominal portion of the opisthosoma is of quite unusual length as compared 

 with the other terga and with the carapace, which appears to be short. The 

 second and third caudal segments, moreover, are long, being much longer than 

 wide, suggesting that the entire tail must have been at least four times, and was 

 very probably five times, as long as the carapace. Since none of the British species 

 in which these skeletal pieces are known, agree with Eoscorpius carbonarius, 

 they cannot be assigned to the genus. Scudder has suggested that Mazonia 

 voodiana, from the same beds as Eoscorpius carbonarius, may be synonymous with 

 it. This view, however, cannot on the evidence be entertained ; because, if 

 correctly drawn, the former is unique in having either a segmented carapace or 

 eight dorsal shields, possibly, indeed, nine, according to Fritsch, between the head- 

 shield and the tail. The ocular tubercle, moreover, is situated almost at the 

 anterior border of the carapace, and the humerus and brachium of the chela are 

 remarkably long and slender. Since none of the British species present these 

 characters, Mazonia, like Eoscorpius, need not be further considered in this 

 monograph. 



The European species, excluding those described by Dr. Peach from Scotland 

 which are omitted from Fritsch's monograph, are referred by this author to the 

 following genera : Cijdoplithalmus, Corda; Microlabis, Corda; Isobuthts, Fritsch; 

 Eobuthus, Fritsch; Feistmantelia, Fritsch ; and Eoscorpiius, M. and W. Anthraco- 

 scorpio, Kusta, is rejected by Fritsch as based upon an immature specimen of 

 Eobuthus; and Eoscorpius is included for the reception of the species described by 

 Dr. Woodward as E. anqlicus. 



Microlabis, possessing only one species, namely, M. sternbergi, Corda, differs 

 from all the other European genera, so far as is known, in the structure of 

 the chelae, which have the brachium long, parallel-sided, and prismatic, the hand 

 or manus short and very narrow, without any bulge on its inner edge, and with 

 no concavity at the base of the immovable digit, which, like the movable, is long, 

 stout, and straight, the two resembling the blades of scissors, the movable being- 

 more than half as wide as the hand. This genus, therefore, may be set on one 

 side. So also must Feistmantelia, based upon a single character, the tuberculation 

 of the pectines. This is probably the same feature as that described by Dr. Peach 



