12 LILIAN SHELDON. 
ment of the surrounding protoplasm such as was observed in 
the very young male pronucleus of P. capensis. The next 
appearance of the male pronucleus is similar to that shown for 
Peripatus capensis in fig. 14 6, where it lies near the 
centre of the egg and is large and nearly spherical. A section 
through such an ovum of P. Balfouri is figured by Mr. 
Sedgwick (15) (Pl. XII, fig. 1), and consequently I have not 
thought it necessary to draw it again. 
Fig. 25 is from a section through an ovum in which the 
male and female pronuclei lie near the centre of the ovum, 
and are apparently about to unite. The female pronucleus 
does not stain, with the exception of its wall, and some chro- 
matin particles which are present in it; it consists of several 
lobes separated from one another by prolongations of the wall 
inwards. The male pronucleus stains very deeply, and, like 
the female, has a lobed structure and contains some chromatin 
granules. The protoplasm round the pronuclei is rather 
denser than over the rest of the ovum. Yolk-spheres are 
scattered in the protoplasm. 
The actual union of the pronuclei I have not seen. The 
resulting segmentation nucleus is similar in all respects to that 
of P. capensis. 
Peripatus Nov@-ZEALANDIA. 
The differences between the stages passed through in the 
maturation of the ovum of the Cape and New Zealand species 
are considerable, owing mainly to the large amount of food-yolk 
in the latter. 
Structure of the Ovary.—The ovary resembles that of 
P. capensis in structure. It is attached, however, along its 
whole length to the ventral wall of the pericardium, instead of 
by its front end only as is the case in the Cape species. In 
one ovary from an animal which was opened in December, 
there was a good deal of yolk, which lay mostly just below the 
non-germinal part of the epithelium. A transverse section 
through this ovary is shown in fig. 26; the only connection 
