DEVELOPMENT OF THE PIG DURING FIEST TEN DAYS. 335 



The polar bodies of this specimen were especially large. 

 They were spherical, and measured '025 mm. and •014 mm. 

 respectively. 



In the five-segment stage (fig. 5) there is one segment dis- 

 tinctly larger and one distinctly smaller than all the others. 

 The remaining three are approximately equal. There is no 

 means of determining to which generation the segments re- 

 spectively belong. It is, however, interesting and important 

 to note that at this early stage there is a very great difference 

 in size between the several segments. 



The next stage I have is one of six days three hours. 

 I had several in this stage, all of which had been treated 

 with Flemming's fluid, and were therefore considerably 

 blackened, owing to the action of the osmic acid on the 

 oil vacuoles. This makes it difficult to determine the 

 number of segments in surface view. The chief feature of 

 all these specimens was easily discernible. This was the 

 presence of one segment very much larger than any of the 

 others. 



One specimen was stained in carmalum and cut into sections, 

 a drawing of one of which is given as fig. 14, PI. 26. In this 

 specimen there are altogether nine segments. One of these is 

 far larger than any of the others. The nucleus of this seg- 

 ment is in an early stage of mitosis. The section I have 

 drawn, however, does not pass through it. The remaining 

 eight segments are of very different sizes. The nucleus in 

 each is in its resting condition. 



The specimen of which fig. 12 represents a section was, when 

 seen in surface view, apparently in a similar stage to that 

 represented by fig. 13. It seems, at any rate, possible 

 that it was really in the two-segment stage, and that one of 

 the segments had by some means burst. 



The section which I have drawn shows one very large and 

 complete segment, and partially surrounding this there is a 

 mass which contains not a trace of nucleus nor any arrange- 

 ment of the oil globules comparable to those of the large intact 

 segment or to those of fig. 13. If this is really the case, 



