THE ANATOMY AND DEVELOPMENT OF PERIPATUS NOV AE-BRITAXXIAE. 13 



In P. capensis, Sedgwick described the segmental origin of the generative organs 

 from the median or generative portions of somites XVI to XX inclusive. The gene- 

 rative ducts arise from the 21st pair of somites (somites of the anal papillae). 'The 

 nephridial portion of the twenty-first somite " says Sedgwick (Monograph p. 96) " does 

 not separate from the median or generative portion but remains in connection with the 

 latter and forms the channel by which the generative part of the coelom communicates 

 with the exterior. The generative ducts are therefore modified nephridia, but it is 

 important to notice that the connection between them and the generative tubes is 

 not to be compared with the so-called funnel of the normal nephridia. The latter is 

 merely a special portion of the lateral portion of the somite, and does not seem to 

 be represented in the twenty-first somite." 



According to Kennel (11), the sexual organs of P. edwardsii {trinidadensis) are 

 nothing else than the metamorphosed segmental organs of the penultimate leg-bearing 

 segment. 



In the last-named species therefore the generative organs arise in one segment 

 only. Thus from the beginning to the end the female generative organs of P. edwardsii 

 and P. capensis appear to differ radically from one another. 



In P. capensis the ovarial cavity acts at once as receptaculum ovorum and re- 

 ceptaculum seminis, and is in this respect unique. 



In P. novae-britanniae the anatomical relations of the infundibula and ovary 

 involuntarily suggest an exact homology with the funnel and end-sac of a nephridium. 

 I have no observations on the development of these organs. 



Uteri. The only parts of the female generative system whose topograph}- is fairly 

 constant, are its two terminal portions, ovary and vagina: what lies between has no 

 regularity whatever in its disposition and it is impossible, from my material, to say 

 whether any particular arrangement is the normal one. In the individual figured 

 in Fig. 12, the outer or vaginal ends of the uteri each contain a pigmented 

 embryo nearly ready for birth. The portion of the uterus which lies posteriorly 

 over the rectum appears from the figure to belong to the right side of the animal. 

 It is really the left uterus and its narrow end passes to the left side and bends 

 under the left nerve-cord to open into the vagina. In another specimen the uteri 

 on being exposed, presented a nearly identical appearance to the one just referred to, 

 but the uterus lying over the rectum in this case turned out to be actually the right 

 uterus and its narrow terminal portion bent down and passed under the right nerve- 

 cord to open into the vagina. 



Each uterus on leaving the region of the ovary passes forwards for a varying 

 distance and then bends sharply round upon itself to lead back to the vagina. These 

 two portions of the n~ sna P e( l uterus may be referred to as the ascending and 

 descending portions respectively. The distal portion of the uterine tubes, that is, 

 the portion which abuts on the receptacula seminis, is much coiled and the stiff 

 coils will not easily unravel in preserved specimens. In Fig. 13, the ascending right 

 uterus, after emerging from the coil, is seen to pass over and then under the 

 ascending left uterus. Up to this point both uteri are directed towards the ventral 

 side of the body-cavity ; but now the ascending right uterus rises to the dorsal side 



