OVUM IN THE CAPE AND NEW ZEALAND PERIPATUS. 291 



han in P. capensis^ and on the outer by the thick germinal 

 epithelium, which is narrower in P. Balfouri than in P. 

 capensis. 



2. The ova arise by a growth of some of the nuclei of the 

 germinal epithelium ; apparently any of its nuclei may give 

 rise to ova. 



3. The ova by July lie at the surface of the ovary, with 

 which they are connected by short thick stalks. Each ovum 

 has a large, round, central nucleus with an excentric nucleolus, 

 surrounded by a layer of protoplasm which is not separated 

 from the protoplasm of the germinal epithelium. 



4. By September the stalks have increased in length, so that 

 the eggs project farther into the body-cavity. The ova have 

 increased in size and are surrounded by a thin shell on all 

 sides. 



5. The ova continue to increase in size, and small round, 

 highly refractive granules of yolk appear in the protoplasm. 

 The nucleus or germinal vesicle of P. capensis has a uniform 

 granular structure, that of P. Balfouri does not stain with 

 the exception of a deeply-staining irregular network in it. An 

 excentric nucleolus or germinal spot is present. 



6. The nucleus passes to the periphery, and is large and 

 round, and almost homogeneous, with only slight traces of a 

 reticulum. 



7. The germinal spot disappears. 



8. The wall of the germinal vesicle becomes irregular in 

 outline and then disappears, its contents becoming fused with, 

 and indistinguishable from, the cell- substance. In P. Balfouri 

 yolk-spheres have made their appearance. 



9. The ovum becomes detached from the follicle, which has 

 grown all round it, so lying in a hollow vesicle. 



10. It probably passes down the stalk into the ovary and 

 there becomes fertilized, since the ovary is full of spermatozoa, 

 and thence makes its way into the uterus. This passage has 

 not been observed. 



11. The youngest uterine ovum observed has no nucleus. 

 In one such ovum a projection containing threads of chromatin 



A A 



