236 LILIAN SHELDON. 



of his work on the 'Development of P. capensis' (fig. 7). A 

 section through the protoplasmic area of this egg is shown 

 in fig. 5. The protoplasmic masses, which in surface view 

 appeared to be separate from one another, are seen to be very 

 closely connected by strands ; in two places two nuclei are seen 

 lying close to one another, and in another a single nucleus is 

 cut through. The yolk, situated below the protoplasm, is 

 segmented. Fig. 6 represents a section of a small portion of 

 the protoplasmic area drawn under higher power, in which a 

 large number of nuclei are crowded close together in a small 

 area of reticulated protoplasm. 



In the next stage the protoplasmic segments with their 

 nuclei extend over a somewhat larger area of the surface of 

 the egg, the nuclei being still very irregularly scattered 

 through the protoplasm. This extension of the protoplasm is 

 shown in fig. 8, which is drawn from the protoplasmic area of 

 a section of this age. The segments are rather more distinct 

 from one another than they are in the eggs so far described, 

 but they are still connected by protoplasmic strands. The 

 yolk is very definitely segmented. Fig. 9 is from a section 

 through an egg of about the same age ; in it the protoplasmic 

 segments are much more distinct than is usually the case at 

 this stage. 



In all the above-described stages many of the nuclei show 

 indications of karyokinetic figures, so that it is probable that 

 all the nuclei are derived by division of the first segmentation 

 nucleus, and it is not necessary to suppose that any process of 

 free-nuclear formation has taken place. 



In the latest segmentation stage which my material has 

 provided the protoplasmic segments extend over rather more 

 than half the surface of the ovum. They are arranged in a 

 regular layer near the periphery, and appear to be more 

 definitely separated from one another than in the previous 

 stages, although it is probable that they are connected by 

 strands which are hidden by the yolk which separates them. 

 Nuclei are present in many of the segments, although some 

 are devoid of them. In the centre of the protoplasmic are^ 



