90 Annals of the South African Museum. 



Sedgwick to be represented by the ducts of the genital organs. This- 

 homology is very evident in Periioatoides and Opisthopatus, in which 

 these glands open on or near the bases of the genital legs. In Peripa- 

 topsis, however, this is not the case, and its single pair of accessory 

 glands have been generally considered homologous with the anal 

 glands of Peripatiis, which are modified nephridia. Such, for 

 instance, is the expressed opinion of Korschelt and Heider (1892) 

 and A. Willey (1898, pp. 16 and 17). The objection to this view is, 

 of course, the fact that these glands discharge into the ductus 

 ejaculatorius and not posterior to it ; but this difficulty is ingeniously 

 surmounted by Korschelt and Heider, who assume (pp. 715 and 716) 

 that the postgenital portion of the body, which must originally have 

 been as much developed as in Peripatus, has been so completely 

 reduced that the anal glands and the genital opening now apparently 

 lie in the same segment. The absence of glands in the genital 

 segment in Peripatus and of postgenital glands in Peripatopsis also 

 doubtless appeared to justify the view that the accessory glands of 

 both genera must be identical. As we now know that accessory 

 glands may occur in both genital and postgenital segments in at 

 least two genera, there is obviously no necessity for adopting. 

 Korschelt and Heider's theory. 



(h) The accessory glands of the postgenital segments. — Except in 

 Peripatus the morphological value of the posterior pair of glands 

 is by no means so clear as in the case of the anterior pair. 



In Peripatus the genital segment is followed by two segments, the 

 first of w^hich is complete and bears a leg and nephridium on each 

 side, while the second or anal segment, although without legs,, 

 possesses in the embryo, according to Kennel's investigations (1886, 

 pp. 70 and 71), a pair of nephridia, which later on disappear in the 

 female but develop into the accessory or anal glands in the male^ 

 Since the postgenital legs may originally have also possessed crural 

 glands, it is evident that the postgenital glands in the other genera 

 may have been derived from — 



(a) These crural glands, 



{h) The nephridia of the first postgenital segment, 

 (c) The nephridia of the second postgenital segment, 

 assuming that all the forms originally possessed two postgenital 

 segments. Sedgwick (1888fl, p. 98) found rudiments of two pairs of 

 postgenital somites in the embryos of Peripatopsis capensis, but he 

 states that they vanish completely in stage F, With them, of 

 course, would vanish the postgenital glands in this genus. 



In Peripatoides, or at least in P. novce-zealandice, the posterior 



