TWO NEW SPECIES OF ONYCHOPHORA. 509 



of embryos which represent a number of stages in the 

 development. It seems tliat not all the ova which pass into 

 the uteri develop. Many of them, either for want of room or 

 for some other reason, fail to advance beyond the segmenta- 

 tion stages, even if they do segment at all, and as the embryos 

 which are successful in the struggle for existence elongate, 

 the unsuccessful ones become wedged in between the con- 

 tinually growing young. 



There seems to be no evidence in favour of the view, which 

 has been put forward more than once, that accompanying 

 parturition there is a resorption of the terminal ends of the 

 uteri. When the pigmented embryo, which measures from 

 20 to 27 mm. in length, is born, that portion of the uterus 

 which contained such an embryo must contract; consequently 

 the wall must thicken and the flattened cells of the lining, 

 being no longer called upon to secrete nutritive material, once 

 more assume their normal form. The embryos are always 

 entirely free in the uterus, that is, there is no organic con- 

 nection between the developing young and the uterine wall, 

 though they are in close contact with each other. From 

 what can be seen in Eoperipatus, it seems much more 

 reasonable to suppose that the embryos pass gradually down 

 the uteri than that the uteri are resorbed at their vaginal 

 ends. 



(/) The Male Reproductive Organs: — Though the 

 female reproductive organs of Eoperipatus differ con- 

 siderably from those of the genus Peripatus^ the male 

 reproductive organs of the former present a peculiar agree- 

 ment with those of the latter. 



The tubular testis communicates with the seminal vesicle 

 by means of a short duct which c>pens into the latter near 

 its anterior end. Close to the posterior end of the seminal 

 vesicle the vas deferens ' arises and coils about in the body- 

 cavity (haemoccel). The vasa deferentia pass backwards, and 



' No distinction is made here between vas efferens and vas deferens, 

 because there seems to be no satisfactory reason for drawing sucli a dis- 

 tinction. 



