116 DE. J, E. T. AITCHISON ON THE ZOOLOGY OF 



Length. Breadtli. Height. 



Fifth caudal segment 9| 4 3J 



Vesicle 5 3 3 



Aculeus 5 



Humerus 6J 



BracMum 8 3j 



Manus 6 4 3^ 



"Hand-back" 4^ 



Movable dactylus 9 



Immovable dactylus 7f 



1 



4 



Pecten G- 



A single specimen, probably a male, was taken between Hari-rud valley and Meshed. 



This Butlms presents affinities with several species known to me, but appears to be 

 different from all hitherto described. Perhaps its most noticeable peculiarity is the 

 entire absence of keels and of a median depression on the upper surface of the fifth 

 caudal segment — a peculiarity by which it may be recognized at a glance from such forms 

 as B. martensii (Karsch) and B. confucius (Simon). With B. arenicola (Simon, Arach- 

 nides, Expl. Sci. Tunisia, p. 51, 1885), however, it is wuth respect to the form of this 

 caudal segment that B. partliorum appears to be allied ; for in B. arenicola i]xh segment 

 is said to be "supra Icevi, hand canaliculato, nee costato.'" But the cephalothoracic and 

 caudal costse are much less strongly developed in the Tunisian form. 



Eoiir species of Buthus have been recorded from the Caucasus. These are B. eupeus 

 (C. Koch, Die Arachn. v. p. 127, fig. 418), B. cognatus (L. Koch, Kauk. Arachn. in Isis, 

 Dresden, p. 58, pi. i. fig. 7), B. caiicasicus (Nordmann, Voy. Russ. merid. iii. p. 731, 

 pi. i. fig. 1), and B. ornatus (Nordmann, torn. cit. p. 732, pi. i. fii?. 2). Although analogy 

 would perhaps lead us to expect to find a greater amount of similarity existing 

 between the Afghan and the Caucasian species than between the Afghan species 

 and those of any other locality, no such similarity can be traced. For B. parthorum 

 may be at once separated from the above-mentioned species by sundry well-marked 

 characters. For instance, in B. evpeus the fifth caudal segment appears to be without 

 denticulations, and the vesicle is thick, with the aculeus curved and short ; in B. 

 cognatus the infero-lateral keels of this same caudal segment are in part strongly 

 dentate, while in both B. caucasicus and B. ornatus tbe aculeus is remarkably short; the 

 former, in addition, has thirty pectinal teeth, and the latter the complete supernumerary 

 series of granules on the fourth caudal segment, as in B. gihhosus (BruUe). 



6. Buthus afghanus, sp. n. (Plate XIII. fig. 4.) 



This species is so nearly allied to B. eiiropcens, Linn, {^occitanus, tiinetamis, of 

 authors), tbe common and well-known S. European and N. African form, that perhaps a 

 comparison between the two will serve as a satisfactory diagnosis of it. 



Cephalothorax. — Anterior keels as in JS. etiropceus ; the space between tbem qu^ite smooth. 

 Posterior keels converging in front, sinuous, and in contact with the posterior termina- 



