Mr. R. I. Pocock on Neotropical Scorinons. 85 



granular at the sides, but the rest of the trunk is entirely 

 smooth in both sexes. The anterior four segments of the 

 tail are smooth beneath and the superior edges are rounded 

 and at most minutely granular. The brachium is smooth 

 above and behind, and the manus is also smooth and only 

 indistinctly eostate. The pectines are larger in the male 

 than in the female, and are furnished with nine teeth in both 

 sexes. The female measures about 52 millim. in length, the 

 carapace being 7" 8 and the tail 30. 



Whether or not Chactas Fuchsii of Berthold is the same 

 species as Van Benedenii I have not been able to satisfy 

 myself. I may point out, however, that the relative measure- 

 ments of the caudal segments in Fuchsii apply exactly to the 

 female of my Van Benedenii, and that what Berthold says of 

 these measurements in his Van Benedenii is not true of mine. 

 Moreover the median eyes in the latter are not grey, but the 

 colour of clear amber. If, however, Berthold has correctly 

 determined the sexes of his species, the female of Fuchsii 

 certainly differs from that of Van Benedenii in having the 

 finger (by which presumably the movable finger is meant) 

 much shorter than the hand (2^ : 4^), that is, shorter by 

 nearly its own length ; and in the male of Fuchsii the finger 

 is only by a third of its own length shorter than the hand. 

 Berthold asserts, moreover, that the carapace of his species is 

 entirely smooth, which is not strictly the case in Van Bene- 

 denii. 



Of the meagre description of Ch. hrevicaudatus of Karsch 

 very little can be made. Very possibly the species may be 

 the young of Van Benedenii or Fuchsii. 



Chactas lepturuSj Thorell. 

 Chactas lepturus, Thorell, Ac. Soc. Ital. Sci. Nat. xix. p. 266. 



The specific name given to this species by Thorell was 

 upset in favour of Thorellii by Karsch, who alleges that the 

 Scorpio lepturus of Palisot de Beauvois is also a Chactas^ 

 although belonging to a different species from that which 

 received the same name from Thorell. 



Karsch bases his assertion as to the generic position of 

 lepturus, Pal. Beauv., upon a specimen in the Berlin Museum, 

 which he believes, for unstated reasons, to be Beauvois's type. 

 It seems a pity, however, that a more favourable selection of 

 the type was not made ; for, seeing that Beauvois asserts 

 that his species had eight eyes and his figure shows that the 

 tail is only as long as the trunk and the carapace is as long 

 as the anterior three segments, whereas Karsch's specimen 



