Species of Opisthophthalmus. 171 



This handsomely coloured species is very closely related to 0. 

 git/its iin d 0. karrooensis. In 0. longicauda the palps are relatively 

 shorter, while the cauda is relatively much longer than in 0. kar- 

 rooensis, the granulation on the carapace and especially on the terga 

 and sterna is coarser, the basal angle of the pectines is not rect- 

 angular in the male, and the vesicular segment is relatively much 

 shorter ; the lateral margins of the carapace are less parallel than in 

 karrooensis, converging towards the front as in gigas. But the main 

 difference lies in the hands of the female, which are flattened above 

 and as broad as the hand-back is long in karrooensis, but strongly 

 convex and much broader in longicauda. On the other hand, loiigi- 

 ca/ula and gigas resemble each other, and differ from karrooensis in 

 not possessing the series of wedge-shaped lamellae (Pocock's stridu- 

 lating organ) on the inner side of the basal joint of the mandibles. 

 In 0. gigas the hand of the female is also convex above, the carapace 

 narrowed in front, and the scape of the pectines not rectangular at 

 the base in the male. 0. gif/as is easily distinguished, however, by 

 its smooth abdominal sterna and the relatively shorter tail. 



OPISTHOPHTHALMUS PATTISONI, n. sp. 



Female (recently killed, in s})irits). 



Colour. Whole animal very dark reddish brown ; the posterior 

 (inner) surface of the legs, the under side of the palps, the vesicle, 

 the interocular area, and the inner part of the hand above somewhat 

 lighter ; the crests and fingers of the palps, the coarser granules on 

 the sides of the carapace, and the maxillary processes of the first 

 two pairs of legs black. 



Carapace scarcely longer than wide, as long as the first two caudal 

 segments taken together ; its interocular area large, quite smooth 

 and polished, finely punctate ; sides of the carapace coarsely granular 

 only in the anterior half, in the posterior half the granules are much 

 less coarse, although still visible to the unaided eye, and there are 

 no very coarse granules bordering the sides of the interocular area 

 behind the middle of the carapace ; the area round the median eye- 

 tubercle nearly smooth ; distance of median eyes from posterior 

 margin contained 3 times in the total length of the carapace ; 

 anterior fork of median groove obsolete. , 



Terga finely granular at the sides, shiny, the anterior segments 

 finely punctate and smooth in the middle, the posterior ones finely 

 roughened in the middle, last segment coarsely granular at the sides. 

 a. All the segments smooth and polished, the last with a 



