286 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 b, 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 (14) (PL III, 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 NovjE-ZEALANDiiE. 



The difi'erences 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 



