518 R[(JH.\I>'D EVANS. 



P. Leuckarti, and finally in Eoperipatus. If instead of 

 shifting forward tliey bad shifted backwards, the condition 

 found in P. Edwardsii would result, and by shifting up- 

 wards that found in Paraperipatus would be brought 

 about. It seems that there are two reasons for this shifting ; 

 fiist, the slightly subterminal position of the anus ; secondly, 

 the shortening of the anal cone. Probably the latter was the 

 more potent element in driving the opening to the uiid-dorsal 

 line in Paraperipatus, the question of space becoming a 

 determining factor in bringing about the change of position 

 of tlie openings. In Paraperipatus, as the anus and 

 genital orifice approached each other, the glands and their 

 openings were forced towards the dorsal aspect of the animal. 



We may conclude that it is possible to homologise the 

 anal glands of Peripatus, tlie pygidial glands of Para- 

 peripatus, and the accessory glands of Peripatoides and 

 Eoperipatus Avith the renal organs, and with one another, 

 without violently twisting the facts known about them, 

 though in many respects we are still treading on uncertain 

 ground. 



There remains to be considered, however, one well-known 

 form, namely, Peripatopsis capensis. In this form the 

 male accessory glands open into the terminal portion of the 

 ductus ejaculatorius. In this feature Peripatopsis is quite 

 unique. In fact, in this genus the relation of the male 

 accessory glands to the ductus ejaculatorius is exactly what 

 it should be, on the view that they are the crural glands of 

 the genital segment. In Balfour's posthumous works the 

 following expression occurs: — "The accessory gland in the 

 male is probably a modification of one of these organs;" i. e. 

 of the crural glands (1). Mr. Sedgwick in his account of 

 the development of the species under consideration Avrites as 

 follows: — "There are rudiments of two pairs of somites 

 behind the somites of the anal papillge in Stage E. One 

 of these is just visible in Stage F. They vanish completely 

 at the end of Stage F. No appendages or rudiments of such 

 are developed in connection with them " (14). From this 



