OVUM IN THE CAPE AND NEW ZEALAND PERIPATUS. 17 
than 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 le 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 
yolks-pheres 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 
VOL, XXX, PART 1,—NEW SER. B 
