104 THE DEVELOPMENT OF 



do not allow me to determine. I have seen no trace of 

 any connection between the nuclear reticulum and the pro- 

 toplasm of the egg. The yolk is granular, the yolk glob- 

 ules ranging considerably in size. The color of the fresh 

 egg is a dirty-white. 



SEGMENTATION. 



The first and second segmentations of the egg take place 

 before the so-called segmentation planes appear, and they 

 are so similar in character that they may be described to- 

 gether. With the first segmentation the protoplasm begins 

 to leave its central position and seek the surface of the egg ; 

 before the second division is completed it has reached the 

 surface, leaving the yolk in the centre. In the process of 

 cell division I have never seen any traces of karyokinesis ; 

 the division seems to be direct, and affects first the nucleus 

 and next the protoplasm. Fig. 2 represents a section 

 taken through the egg at the second segmentation, the 

 plane passing through each of the resulting nuclei and the 

 as yet unsevered protoplasm connecting the two potential 

 cells. It exactly parallels, except in being nearer the sur- 

 face, the phenomena of the first segmentation. The two 

 nuclei have taken their places near the extremities of the 

 elongate protoplasmic mass and each is vacuolated and 

 provided with a chromatin reticulum. The protoplasm 

 at either end shows the radial ramifying condition char- 

 acteristic of the same material in the uusegmented ovum ; 

 but between the two nuclei extends a smooth cord, in the 

 interior of which the granules present the appearance of 

 longitudinal striae. There is, besides, in this region an 

 appearance as if the connecting band were double. As 

 will be seen at either end, the protoplasm has reached the 

 surface ol the egg and surface views show that it there 

 extends itself in the same stellate manner as was seen in 



