44 



clently by Plesiobuthus and Isometrus, the former being a de- 

 scendant of Butlius and the latter of Lychas, it will be difficult 

 to find valid reasons for upholding the groups Buthinse and 

 Oentrurinae. 



31. Plesiobuthus paradoxus, sp. n. 



Colour mostly a fairly uniform yellow ; ocular tubercle and 

 frontal area of carapace infuscate ; middle line of tail and its 

 superior and supero-lateral crests, as well as the sides of the 



vesicle and the three inferior 



C. B. A. keels of the 5th caudal seg- 



ment, infuscate ; chelae and 

 legs yellow, with keels infus- 

 cate. Carapace as long as 

 the oth caudal segment ; finely 

 granular. Terga closely gran- 

 ular. Sterna smooth, finely 

 granular at the sides ; the 

 last with two granular crests, 

 the median pair being obso- 

 lete. Tail about five and a 

 half times as long as the 

 carapace, the first three seg- 

 ments subequal in width, 

 4th much narrower than 3rd 

 and 5th than 4th ; median 

 lateral keel present only on 

 the posterior half of the 1st 

 segment, absent on the rest ; 

 inferior median keels smooth on segments 1 and 2, scarcely 

 granular on 3 and 4; the rest of the keels granular: intercarinal 

 spaces of tail smooth, or at most finely granular; vesicle narrower 

 than 5th segment, smooth, punctured below ; aculeus long and 

 lightly curved. Chelc? with humerus, braehium, and hand granu- 

 larly crested ; hand wider than braehium ; underhand about half 

 the length of the movable digit ; movable digit much longer than 

 carapace, armed with 11 rows of teeth. Leys with femora and 

 patellae armed with granular crests. Pectines long, furnished with 

 37 teeth. 



Measurement* in mm. Total length 56, carapace 6, tail 34, 

 movable digit 6-5. 



Loc. Northern Baluchistan (Maynard $ 



Fig. 1 1 . Plesiobuthus paradoxttg. 



A. Extremity of 3rd leg, from above. 

 B. Ditto, from the side. C. Vesicle 

 and aculeus. 



Genus ISOMETRUS, Hempr. & Ehrenb. 



Isometrus, Hempr. < Ehr. Symb. Phi/s., Scorp. p. 3, 1828; also 

 of Tkorell, Karsch, Simon, Pocock, etc. (in part) prior to 1891; 

 Eraepelin, Jb. Hamb. wiss. Anst. viii, p. 244, 1891, and of 

 subsequent authors. 



Terga of carapace with only a median keel. Tail with a large 



