THE ANATOMY" AND DEVELOPMENT OF PERIPATUS NOVAE-BRITANNIAE. 11 



New Britain species and from the Cape and Australasian forms. The ovarian tubes 

 in the subgenus Peripatus (see above, p. 3) have thick walls composed, according to 

 Gaffron, of exactly the same layers as the uterine wall, namely, peritoneal investment, 

 tunica muscularis, tunica propria and [germinal] epithelium. The ova mature in situ 

 (Text-figure 2) and make low projections towards the lumen of the ovarian tube, the 

 basal membrane (tunica propria) of the germinal epithelium maintaining its even course 

 below the ova. They may be called "epithelial ova" in contradistinction to the 

 " follicular ova " of the other forms. 



In the other three subgenera (see p. 3) the wall of the ovarian tubes is thin 

 and the ova do not retain their epithelial position during maturation, but they cause 

 the wall of the ovary to project in the form of follicles which are attached to the 

 ovary by longer or shorter stalks and hang freely into the central division of the 

 body-cavity (haemocoel) (Fig. 18). In P. novae-britunniae I do not find a tunica 

 muscularis distinct from the peritoneal investment of the ovary, and there is no 

 regular tunica propria. In these respects, the present species resembles P. capensis 

 and P. novae-zealandiae (Sheldon 21). 



These facts have their bearing on the interpretation of the morphological character 

 of the ovarian tubes themselves. It is possible that these are not strictly homologous 

 structures throughout the genus Peripatus (see below, section on Receptaculum ovorum). 



The ova of our species contain granular protoplasm and are without yolk; when 

 fully formed they measure about -11 mm. in diameter. In point of size they are 

 therefore intermediate between the Neotropical and the Cape species. 



Receptiirnhi seminis. The infundibuliform oviducts, which have the shape of ram's 

 horns, lead direct from the ovary to the corresponding receptacula seminis. 



Before reaching the receptaculum seminis, each oviduct communicates by a short 

 canal with the uterus. In Fig. 17, this cross- way has the appearance of being a 

 secondary connection. Gaffron (6) has described the origin of the receptaculum 

 seminis by a looping up of the genital duct, the two folds which combined to produce 



Fig. 3. Diagram to illustrate the mode of formation of a receptaculum seminis with its two ducts. 



[Simplified after Gaffron.] 

 In A the oviduct is simply looped. 



In B the convex portion of the loop has begun to enlarge and to cause lobe-like projections. 

 In C the angles of the loop have met and fused. 



the loop then fusing together, so that the lumen of the duct becomes continuous 

 past the receptaculum seminis with which it is connected by two ducts (Text-figure 3). 



2—2 



