TWO NEW SPECIES OF ONYCHOPHOBA. 527 



ancestor, which is more closely represented in Eoperipatus 

 than in any other genus ; for this genus combines the most 

 complete development of the two posterior pairs of legs with 

 what seems to be the most primitive ovum. Peripatoides 

 lacks the last pair of legs, though its development is as 

 primitive as that of Eoperipatus, and, even more so, in that 

 oviparity occurs. However, the actual development is so 

 little changed in Eoperipatus, that it may well lay claim to 

 being, on general grounds, the most primitive genus among 

 the Peripatidas. 



Before bringing the present part of my account of Eo- 

 peripatus to its close, it seems necessary to make a brief 

 reference to the geographical distribution of the Peri- 

 patidiK. 



About two years ago M. Bouvier published a preliminary 

 note on the geographical distribution and the evolution of 

 Peripatus (4), in which he came to the following conclu- 

 sions : first, that the African, American, and Australasian 

 groups are definitely related to the Continents the names of 

 which they bear ; secondly, that it appears quite certain 

 that Central America and the Caribbean Region have been 

 the centre of origin and migration of the species of Peri- 

 patus. From the above-mentioned regions they are supposed 

 to have travelled towards the east to Africa, and towards 

 the west to Australia. 



The first conclusion has been adopted in the present 

 memoii", and the discovery of the Malay forms considerably 

 strengthens it. But the same discovery seems to weaken the 

 second conclusion, which, to say the least, has been prema- 

 turely formed. 



The only feature in which the American species seems to 

 be more primitive than the Malay ones is the possession of a 

 greater number of segments in all of them. The number of 

 denticles in each blade of the jaws of P. tuberculatus 

 (Bouvier) seems in some respects to show a inore primitive 

 condition than that which occurs in the Malay forujs; but in 

 other respects the jaws of the latter seem to present the more 



