ARCILEOCTONUS. 



17 



from the same locality and horizon, and an entire tail from the Sandwell Park 

 Colliery, Birmingham. It is not unlikely that the tail from Mansfield belonged to 

 an example of the same species as the owner of the chela, from the same locality ; 

 and this tail is structurally closely similar to the one from Birmingham. Dr. 

 Woodward, therefore, was perfectly justified in referring the three to the same 

 species. In this I propose to follow his example until evidence to the contrary is 

 forthcoming. Nevertheless, in view of the possibility of the chela and caudal 

 segments from Mansfield belonging to different species, perhaps to different genera, 

 it seems advisable to select one of the specimens as the type of the species. I 

 select, therefore, the chela, because the species may be distinguished at once from 

 all other Carboniferous Scorpions in which the chela is known, by the shape and 

 proportions of the segments of this appendage. 



Fig. 2. — Palaomachus anglicus (Woodward) ; copied from Quart. Journ. Geol. Soc, to], xxxii, pi. viii. 

 a., chela from Mansfield ; h., five caudal segments from Mansfield ; c, entire tail from Sandwell Park. 



The only Carboniferous Scorpion described with fingers as short as in P. 

 anglicus is the type of Eobutlms rahovnicensis, Fritsch. Assuming that the figure 

 and description published by Fritsch are correct, P. anglicus cannot be assigned 

 to the genus Eobuthus, because in the type species of the latter the hands are 

 much longer than the digits, and a little narrower than the brachium. 



Genus ARCHiEOCTONUS, nov. 

 1883. Eoscoiyivs, Peach (in part), Trans. Roy. Soc. Edinb., vol. xxx, p. 398. 



Generic Characters. — Distinguishable, so far as is known, from all other genera 

 of Carboniferous, as well as of recent Scorpions, by the extreme shortness of the 

 legs, those of the fourth pair, when extended, not nearly attaining the posterior 

 extremity of the abdominal portion of the opisthosoma (pre-abdomen). The 

 individual segments of the legs are not very unequal in length, and the femur of 

 the fourth is much shorter than the carapace. The hand of the chela is small, 



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