568 CLASS II. ONYCHOPHORA. 



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 younger (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 

 and indeed of the male. Such spermatophores are found on 

 the bodies of both males and females from July to January, 

 but they appear to be most numerous in the autumn. It has 

 been suggested 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 ; but having 

 regard to the thickness and the toughness of the skin and the 

 absence of any cutaneous secretion capable of dissolving the 

 coat of the spermatophore, it seems unlikely that this should 

 occur. We therefore venture to make the suggestion, though 

 we cannot offer any facts in support of it, except the swallowing 

 of the cuticle above mentioned, that the creatures lick the 

 spermatophores off their bodies or otherwise devour them and 

 that the spermatozoa are set free in the stomach and make their 

 way through its soft walls and through the body cavity to the 

 ovary or receptaculum seminis. The testes are active from 

 June to the following March. From March to June the vesiculae 

 of the male are empty. In some species (Australasian, neo- 

 tropical, etc.) the spermatophores are large and have horny 

 cases ; nothing is known as to their deposition. 



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 other species the uterus, which is always 

 pregnant, contains embryos of different ages, and births take 

 place all the year round. In all species of Pcn'patus the young 

 are fully formed at birth and differ from the adult in little more 

 than in size and colour. The number of spiniferous rings on the 

 antennae appears to increase by intercalation after birth and it 

 is possible that there may be other slight additions, but speaking 



