412 Mr. R. I. Pocock on some 



Tail short, barely three times the length of carapace ; the 

 third segment about as wide as long. 



Hand not keeled, broad, completely covered above with 

 fine close-set granules. 



Mandibles with three stridulating-bristles on the inner 

 surface of its basal segment. 



Pectines with 25 teeth running right up to the base of the 

 edge of the shaft. 



Measurements in millimetres. — Total length 75 ; length of 

 carapace 11, of tail 33. 



Loc. Transvaal. Specimen procured from Mr. O. E. 

 Janson. 



Most nearly allied to 0. opinatus as diagnosed by Kraepelin, 

 but apparently differing in the granulation of the lt Spiegel " 

 of the carapace, the carination of the last abdominal sternite 

 and of the first caudal segment below, structure of hand, 

 spine-armature of posterior tarsi, &c. 



Genus Opisthacanthus, Pet. 

 Opisthacanthus fulvipes, sp. n. 



Colour a tolerably uniform reddish brown, redder on the 

 chelae, the crests of which, as well as the fingers, are nearly 

 black; legs and vesicle clear yellowish red. 



Differs from the species common in the province of Natal, 

 which I believe to be identical with 0. validus of Thorell, in 

 having the brachium and hands flatter and much less coarsely 

 sculptured, the reticulation being finer and more evidently 

 punctured ; the superior prominence on the anterior surface of 

 the brachium is also noticeably larger ; the vesicle of the tail 

 is distinctly higher and the granulation much coarser, its 

 height being just about equal to the length of the carinate 

 portion of the lower surface of the first segment and ex- 

 ceeding the width of the latter (in validus it is much less). 

 The pectines are much longer as compared with their basal 

 width than in validus. The tarsus of the fourth leg is armed 

 below with 4 spines behind, 3 in front, one of the spines 

 being upon the inferior distal angle (in the Natal form, 

 validus, the lower side of the fourth tarsus is armed with 3 

 spines behind and 2 in front, with a bristle on the inferior 

 distal angle). 



In the spine-armature of its feet and the colour of its legs 

 this species resembles the large Transvaal species which I 

 described as kevipes, but which Kraepelin, wrongly I think, 

 identified with asper, Pet.*. 0. fulvipes may be recognized, 

 * I suspect mv Nyasa species rugiceps is in reality the same as asper, 

 Pet. 



