OCR Text |
Show 118 MR. R. I. POCOCK ON THE SCORPIONS [Mar. 18, it belongs ; moreover quite at the distal end of the digit, the apical tooth of the median rows becomes enlarged, slightly separated, and constitutes with the original apical tooth a transversely set pair. Thus in this species we clearly see how the arrangement met with in Uroplectes has been brought about. Genus UROPLECTES, Peters. (Plate XIII. figs. 3-5, and Plate XIV. fig. 5.) Uroplectes, Peters, Monatsb. Ak. Wiss. Berl. 1862, p. 512-type ornatus, Peters. Tityus, Thorell, Etudes Scorpiol. p. 8 (1876) ; not Tityus, C. Koch, 1836. Hab. S. Africa. This genus is closely allied to the preceding and can only be distinguished from it by the arrangement of the denticles on the chelae. The denticles of the external series are the same in the two genera, but the internal series is composed, in Uroplectes, oi a series of pairs of teeth. These appear to have arisen, as, indeed, the) have arisen to a less extent in L. occidentalis, by the separation of the apical tooth of each median row and by its subsequent approximation to the enlarged and slightly separated tooth which forms the secondary anterior end of the series distal to the one from which the external tooth of each pair originated. It thus comes about that in this genus the internal series appears to have been formed, as has the external series, merely by the outward bending of the anterior termination of the median rows. Both Uroplectes and Lepreus are found in S. Africa, and I think there is very little doubt that ultimately, owing to the discovery of intermediate forms, all the species will have to be united into one genus Uroplectes. The genus Tityus was established in 1836 by C. Koch upon a S.American species named Scorpio bahiensis by Perty. Clearly, then, bahiensis is the type of the genus Tityus ; but since this species is referable to Lsometrus of Ehrenberg, a name which antedates Tityus, and since a generic name should never be transferred from its type, it follows that Tityus must be a synonym of Lsometrus. In years subsequent to 1836 and especially in 1845 (Die Arachni-den, xi.) C. Koch referred many more species to his Tityus. One of these, a S.-African form, T. lineatus, was selected by Dr. Thorell as the type of his Tityus ; but since this form differs radically from T. bahiensis, it is clear that Dr. Thorell's Tityus is not equivalent to Tityus as C. Koch originally applied the name. And since this transference of a generic name from one typical species to another 1 1 I am aware that in the Ann. Nat. Hist. 1888. vol. ii. p. 245, in connection with the names Scorpio, Heteromctrus, and Palamnceus, I was the advocate of another system. But further reflection and wider experience has led m e to change the view there set forth : consequently I now think that palmatus is and must always be the typical species oi Heteromctrus, and that if palmatus be congeneric with africanits, then Heteromctrus must be synonymous with Scorpio, and that in no case can the generic name Hcterometrm be transferred from its type palmatus to the second species spinifer, which is consequently a Palamnceus. |