138 MB. R. I. POCOCK ON THE SCORPIONS [Milf. 18, 



large blunt tubercles : manus very wide, wider than bracliiuni, 

 almost wholly smooth, not carinate and not granular ; movable 

 dactylus half as long again as the "hand-back," bearing a 

 distinct though small internal basal lobe which fits into a corre- 

 sponding hollow in the immovable dactylus, so that when closed a 

 sinuate space is left between them at the base ; the internal series 

 composed of nine sharp separated teeth, the external series of eight 

 pairs of teeth. 



GhelicercB. The movable dactylus armed above with three strong 

 teeth, whereof the posterior is bifid, and below with two sharp teeth ; 

 the two inferior teeth of the immovable dactylus well developed 

 though smaller than the other teeth of this appendage. 



Legs. Femur and patella anteriorly finely granular ; the femur 

 of the three posterior pairs carinate above and below, the pa- 

 tella of all of them carinate anteriorly ; tibice of the fourth pair 

 armed distally with a spur, libise of the other pairs unarmed ; coxce 

 smooth. 



Pectines projecting considerably beyond the distal extremity of 

 the fourth pair of coxae, bearing 19 or 20 similar teeth. (The left 

 pecten presents the curious abnormality of having the two apical 

 teeth united.) 



Stigmata slit-like. 



Measurements in millimetres of (^S) specimen. — Total length 59 ; 

 cephalothorax, length 7*5, width 8 ; distance of eyes from posterior 

 margin 4"5 : length of tail 42 ; of 1st segment 5 ; of 2ud 6 ; of 3rd 6v ; 

 of 4th /-S ; of 5th S'S ; of vesicle 4-5 ; width of 1st 4-3 ; of 3rd 4*5 ; 

 of 4th b'7 ; of 5th 5 ; of vesicle 3*3. Palpi — humerus, length 7 ; 

 brachinm, length 7'7 ; width 3 ; manus, width 4'5 ; length of "hand- 

 back " 6"3 ; movable dactylus 2. 



A single specimen ticketed W. Africa, from the collection of Dr. 

 (now Sir John) Kirk. 



This species differs from R. dentatus in having the under surface 

 of third, fourth, and fifth caudal segments smooth ; in R. dentatus 

 they are described as thickly granular. From R. bultneri^ it differs 

 iu having the keels on the tail much more feebly developed and in 

 having no granular keels on the hand. 



Rhoptrurus jacksoni, sp. n. (Plate XIII. fig. 1.) 



Colour of cephalothorax and abdominal tergites fusco-ochraceous, 

 the central and lateral eyes and lateral margins of the cephalothorax 

 and tergites dull black. Chelicerce iiifuscate distally above ; dactyli 

 of palpi infuscate, yellow only at the tips ; aculeus black in its hinder 

 half; the rest of the animal, i. e. the legs, tail, palpi (all but fingers), 

 and lower surface of the trunk, clear ochraceous. 



Cephalothorax very lighily and widely emarginate in front ; its 

 posterior width considerably greater than its length ; almost wholly 

 covered with coarse granulation, some smooth tracts extending 



^ Since the above was written the Museum has received two female speci- 

 mens of B. hiitincri from Eio del Rey, W. Africa. 



