CHAPTER VIII. 



The Egg-Cell or Ovurl 



In the preceding chapter we sketched the history of the " ovum- 

 theory," which expresses the now famihar fact that every 

 organism, reproduced in the ordinary way, develops from a 

 fertiHsed egg-cell. It is now necessary to attend more carefully 

 to the essential characters and history of this " primordium 

 commune," this common starting-point of life, leaving the details. 



Animal Cell, showing the chromatin elements of nucleus 

 {a) in a long coil, and the protoplasmic network (d) round 

 about. — From Carnoy. 



along with the other problems of development, to a special 

 volume devoted to Embryology. 



§ I. Structure of the Ovum. 



essential features of any 



other 



G 



-The ovum presents all the 

 animal cell. There is the 



