.264 LILIAN SHELDON. 



eggs, the yolk is rendered rauch less brittle than after any other 

 methods which I have tried ; the protoplasm and nuclei are 

 well preserved, and also the egg-shell expands and lies at some 

 distance from the periphery of the ovum, and so can easily be 

 removed. The eggs were all stained with picro-carmine, and 

 passed through the various strengths of alcohol in which a 

 small quantity of picric acid was dissolved. 



The embryos, with the exception of a few quite old ones, 

 were all of stages between those shown in figs. 10 and 15 in 

 my last paper (3), that is, they came in age between those 

 received in December and April respectively. 



My material is again very incomplete, and the new stages 

 which I shall describe, though they throw some light on the 

 early development, are very few, and do not unfortunately by 

 any means fill up the gaps which were left in the account of 

 the development given in my last paper (3); but it seemed 

 advisable to publish my results, in the hope that they might 

 prove useful if anyone should have the opportunity of working 

 on the development of this interesting species with a better 

 supply of material than I have been able to obtain. 



The ovum, which represented the latest segmentation stage, 

 described and figured (fig. 10) in my last paper (3), was one 

 which was taken out of the uterus in December. In it the 

 nuclei were present round slightly more than half the ovum, 

 lying in small masses of branched protoplasm. The central 

 one of these nuclei lay on the surface and showed signs of 

 karyokinetic figures. There were also two or three proto- 

 plasmic masses in the central yolk. I have now (in the 

 January lot) several stages later than this, which show that the 

 nuclei in the centre of the surface of the ovum beneath which 

 they lie multiply with considerable speed and very much more 

 quickly than those over the rest of the ovum, a condition 

 which is shown in fig. 4, until by their repeated increase the 

 egg acquires the form shown in fig. 11 (3), which represented a 

 transverse section through an April ovum. In the ovum there 

 figured there is a specially-marked area of reticulate proto- 

 plasm, containing a large number of nuclei extending through 



