KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 21. N:0 9. 21 



composed of a still greater number of small plates (in E. carbonarius at least eleven), 

 whilst in recent scorpions but three, sometimes^) only two of these »lamellas dor- 

 suales» are present. ^) 



If the figure of Eoscorpius euglyptus Peach ^) showing the ventral side of the ani- 

 mal, is correct, this species differs also widely from existing scorpions with respect 

 to the shape of those parts which are situated between the mandibles and the combs. 

 In recent scorpions, the coxa3 of the second pair of legs are directed inwards, trun- 

 cated longitudinally at their inner ends, and they meet or unite in the mid-line of 

 the body. From the anterior side of each of these coxse, a large, oblong, lanceolate 

 or semi-ovate lobe, the maxillary lobe of the second pair of legs, projects; the lobes 

 meet in the mid-line of the body and are enclosed by two other lobes directed for- 

 wards, the maxillary lobes of the first pair. These last named lobes, in fact, proceed 

 from the anterior margin of the coxa3 of the first pair of legs; and like the lobes of 

 the second pair, they reach as far as the opening of the mouth. The arrangement of 

 these parts in Eoscorpius euglyptus, is altogether different. The coxte of the second 

 pair are directed obliquely inwards and forwards, their inner ends are obliquely trun- 

 cate and acuminate, and they do not meet, but leave au intermediate space filled 

 by two oblong contiguous plates, which do not even reach so far forwards as the in- 

 ner apex of the coxse. These plates are by Peach considered as parts of the sternum 

 (see above, p. 12) and by Scudder*) supposed to be »sternites of the second thoracic 

 segment»; they correspond perhaps to the maxillary lobes of the second pair of legs. 

 Nothing coraparable to the maxillary lobes of the first pair is to be seen in Peachs 

 figure. — The real sternum (»metasternum») of Eoscorpius euglyptus is large and nearly 

 quadrate and, as stated above p. 20, is composed of three different parts, viz. two 

 large lateral plates and a small plate in front of them. In shape, it much resembles 

 the sternum of Palseophonus and the recent Pandinoidas, which also have a large quad- 

 rato-pentagonal sternal plate. But the sternum of the Pandinoida3, like that of other 

 recent scorpions and of Palgeophonus, is formed of a single plate, though a longitudi- 

 nal groove along its middle and a transversal groove near its apex, seem to indicate 

 that it was originally made up of three separate plates disposed in the same manner 

 as in Eoscorjnus euglyptus. 



Very different, and no doubt even generically distinct forms have been united 

 under Eoscorpius. We have already mentioned the difference in the shape of the ce- 

 phalothorax of for instance E. injlatus Peach and E. tuherculatus Id., as well as the great 

 dissimilarity in the number of the rows of the pectinal lamellas of E. carbonarius Meek 

 & Worthen and E. euglyptus Peach, which latter species, in consequence of this differ- 

 ence, may be made the type of a new genus {Centromachus n.), to which also the 



') Conf. ScuDDER, loc. cit., p. 20. 



^) Peach describes the combs of Eoscorpius tuberculatus in the following terms: »They seem to be made 

 up of a broad triangulär rachis ornamented with an irreg-ular embossed scale-like pattern, which reminds 

 one of that on Eurypterus and Pterygotus, and edged at the lower side with a row of comparatively large 

 leaf-like teeth.» (1. c, p. 399). 



3) L. c, Pl. XXII, fig. 3a. 



*) Loc. cit., p. 20. 



