PLESIOBUTHUS. 43- 



The two known British Indian genera* may be tabulated a. 

 follows : 



a. No vesicular spine beneath aculeus ; terga 



tricostate ; protarsi of anterior legs de- 

 pressed and thickly fringed with hairs. . . . PLESIOBUTHUS, p. 43. 



b. A strong vesicular spine beneath aculeus ; 



terga with only one median crest, protarsi 

 of anterior legs not depressed and not 

 fringed with hairs IsOMETitrs, p. 44. 



PLESIOBUTHUS, gen. nov. 



Superficially closely resembling Buihus. 



Anterior pedal s^wr very long, stout, undivided but hairy, much 

 larger than the posterior spur ; a conspicuous spiniform process 

 from the protarsus projecting downwards alongside the posterior 

 spur, so that there appear to be three pedal spurs. Protarsus 

 of 1st, 2nd, and 3rd legs strongly depressed, with sharp fringed 

 posterior edge ; tarsi also depressed though to a lesser extent, 

 and hairy; claw-lobe very short and tuberculiform ; claws very 

 long, nearly as long as the tarsus and nearly straight. Immovable 

 fang of mandible armed below with 1 or 2 teeth. Finger of 

 chela armed with many rows of teeth, the enlarged teeth of 

 the inner series placed near the middle of the rows of the median 

 series. Carapace with straight anterior border, four lateral 

 eyes on each side and carinate ocular tubercle, but without other 

 keels. Terga tricostate, lateral crests weak. Tail as in Buthus, 

 but somewhat depressed, the supero-lateral keels very strong on 

 segments 1-3 ; vesicle without spine beneath aculeus. Sternum 

 triangular. 



Type and only known species, P. paradoxiis. 



Distribution. Northern Baluchistan. 



This genus so closely resembles Buthus in a general way, and 

 particularly that species, inhabiting the same area, which Birula 

 has recently made the type of his subgenus (? genus) Liobuthus, 

 that it is hard to believe the likeness is not due to actual affinity. 

 The resemblance, however, is exactly paralleled by that which 

 obtains between Isometrus and Lychas ; and this, in the present 

 state of our knowledge touching the constancy of the tibial 

 spurs, is assumed to be due to similarity of surroundings and 

 mode of life ; and since the resemblance in the latter case is 

 attributed to the causes named, there appears to be no logical 

 ground for doubting their efficacy in producing the similarity 

 observable between Plesiobuihus and Liobuthus. But if in the 

 future it be sho\vn that the tibial spurs have been lost indepen- 



* In the British Museum there is an example of a Central- American species 

 of Centrums (C. infamatus) ticketed Ceylon. This locality is proljably 

 erroneous, and due to the misplacement of a label. If accurate the specimen 

 must ha\e been artificially introduced, and need not be considered in the 

 present work. 



