THE AFGHAN DELIMITATION COMMISSION. 117 



tions of the internal intermediate keels, and not connected by means of a conspicuous 

 transverse series of granules with the external intermediate keels. All the keels less 

 pronounced than in B. europceus. 



Tergites. — Anterior six bearing three keels. In all the specimens of B. euro-pans 

 that I have seen, the lateral keels are absent on the first, and absent or nearly so on the 

 second tergite. But in B. qfghantts they are clearly expressed on both the first and the 

 second. 



Sternites as in B. europceus. 



Tail as in B. europceus, the inferior keels of the second and third segments and the 

 infero-lateral keels of the fifth being dentate in the manner which is so characteristic 

 of that species. 



Chela. — Humerus and brachium as in B. europceus, but the terminal segments are 

 very different. The man its is thicker, and the dactyli considerably shorter, the immovable 

 dactylus being only about the length of the " hand-back." Moreover, this dactylus is 

 furnished with a deeper basal excavation for the reception of a larger lobe on the movable 

 dactylus. 



Two specimens, probably males, between Hari-rud valley and Meshed. 



In spite of the many points of resemblance between this species and B. europceus, three 

 well-marked differential characters can be made out for it : — (1) The posterior thoracic 

 keels converge and join the internal intermediate keels ; (2) the first two tergites are 

 tricarinate; (3) the "hand-back" is almost equal in length to the immovable dactylus. 



The resemblance between the two species is most noticeable in the structure of the 

 tail. 



Measurements (in millimetres) of the type specimen : — 



Length. Breadth. Height. 



Total 37 



Cephalothorax 5| 



Tail 29 



Manus 5 3| 2f 



"Hand-back" 4| 



Movable finger 5^ 



Immovable finger 4| 



Genus Orthodactylus. 



Orthodactylus, Karsch, Berl. ent. Zeits. xxv. p. 90 (1881). 

 Butheolus, Simon, Ann. Mus. Genov. xviii. p. 248 (1883). 



7. Orthodactylus schneideri (L. Koch). (Plate XIII. fig. 5.) 



Buthus schneideri, L. Koch, Naturw. Bcitr. Kennt. Kaukasuslander-Kaukasische Arachnoideen, p. 61 

 pi. ii. fig. -4, in Isis, Dresden, 1878. 



Orthodactylus olivaceus, Karsch, torn. cit. p. 91. 



Butheolus aristidis, Simon, torn. cit. p. 238, pi. viii. fig. 23. 



This synonymy was made out by Dr. Karsch (Berl. ent. Zeits. xxx. p. 76, 1886), and is here repro- 

 duced. 



SECOND SERIES. — ZOOLOGY, VOL. V. 18 



