I O PERIPATUS 



the mouth, and of working them alternately backwards or for- 

 wards. This is readily observed in individuals immersed in water. 



Breeding. 



All species are viviparous. It has been lately stated that 

 one of the Australian species is normally oviparous, but this has 

 not been proved. The Australasian species come nearest to laying- 

 eggs, inasmuch as the eggs are large, full of yolk, and enclosed 

 in a shell ; but development normally takes place in the uterus, 

 though, abnormally, incompletely developed eggs are extruded. 



The young of P. capensis are born in April and May. They 

 are almost colourless at birth, excepting the antennae, which are 

 green, and their length is 10 to 15 mm. A large female will 

 produce thirty to forty young in one year. The period of gesta- 

 tion is thirteen months, that is to say, the ova pass into the 

 oviducts about one month before the young of the preceding year 

 are born. They are born one by one, and it takes some time 

 for a female to get rid of her whole stock of embryos ; in fact, 

 the embryos in any given female differ slightly in age, those next 

 the oviduct being a little older (a few hours) than those next the 

 vagina. The mother does not appear to pay any special attention 

 to her young, which wander away and get their own food. 



There does not appear to be any true copulation. The male 

 deposits small, white, oval spermatophores, which consist of small 

 bundles of spermatozoa cemented together by some glutinous 

 substance, indiscriminately on any part of the body of the female. 

 Such spermatophores are found on the bodies of both males and 

 females from July to January, but they appear to be most nume- 

 rous in our autumn. It seems probable that the spermatozoa 

 make their way from the adherent spermatophore through the 

 body wall into the body, and so by traversing the tissues reach the 

 ovary. The testes are active from June to the following March. 

 From March to June the vesiculae of the male are empty. 



There are no other sexual differences except in some of the 

 South African species, in which the last or penultimate leg of the 

 male bears a small white papilla on its ventral surface (Fig. 6). 



Whereas in the Cape species embryos in the same uterus are 

 all practically of the same age (except in the month of April, 

 when two broods overlap in P. capensis), and birth takes place at 

 a fixed season ; in the Neotropical species the uterus, which is 



