4 Mr. R. I. Pocock on the 



Schizonotus presents a strong general likeness to Thely- 

 phonus in the form of the body, structure of limbs, &c. The 

 telson, however, consists of a single short segment, and the 

 carapace being rather shorter, has left a larger space between 

 its hinder border and the first abdominal tergite ; but this 

 area, otherwise unprotected, is covered by a single or a paired 

 sclerite, which may be either a special development or one of 

 the original cephalothoracic tergites. In any case the result 

 of this segmentation of the carapace is the power to flex the 

 two posterior somites in a vertical plane, the joint being 

 situated between the fourth and fifth ajiipendages. There 

 appears usually to be a single pair of respiratory stigmata 

 situated behind the first sternite, as in Tkelyphonus. The 

 posterior pair that are developed in Thelyphonus appear to be 

 t'unctionless, but upon the third, fourth, and fifth sterna 

 (morphologically the fourth, fifth, and sixth) close to the 

 posterior margin and behind the muscular imj^ressions a pair 

 of dusky patches are visible. These a])pear to be some 

 internal organs seen through the semitransparent cuticle, and 

 I believe they are the homologues of the three posterior pair 

 of lung-sacs of the Scorpion *. In one species described by 

 Dr. Thorcll — ;S'. Camhridgii — two eyes are present; but 

 most interesting of all is the disappearance of the respiratory 

 stigmata and the fusion f of the first two sterna of the abdo- 

 men, which leaves only ten for this region. This species is 

 of interest in connexion with the possible derivation of the 

 Solifugcv from this group. 



The third group of Pcdipalpi — the Phrynidaj — are of 

 interest inasmuch as in all the characters that they depart 

 trom the Thelyphonida^ they approach the true Spiders or 

 Arancffi. The whole body is very much shorter than in the 



opercula in the Mygalomorphse, while the posterior lung-sacs belong to a 

 somite which has no free sternite. This view is entirely opposed to 

 Macleod's hypothesis respecting the derivation of the lung-books of the 

 spiders. 



* These structures have not, I believe, been previously noticed, but 

 they are certainlv visible in both the specimens of this genus that I have 

 seen. For affording me an opportunity to examine these examples I am 

 indebted to the kindness of the Ilev. O. P. Cambridge, who with great 

 liberality sent to me the types of the two species he has described. That 

 named tenmcaudata is referable to the so-called genus Tripcltis of 

 Thorell, having the posterior cephalothoracic tergite paired. 



t Dr. ThorelTs words describing this feature are "... nee limiiem inter 

 scuta ventralia hn et '2m, nee spiracida ccrto discernere j)otin" (Ann. 

 Mus. Genov. xxvii. p. 560, 1889). This author ascribes only eleven terga 

 to the abdomen. I cannot but think, however, tiiat he overlooked the 

 first small tergite, which is present in the two specimens seen by me. 



