The Mammal. 



129 



course, and is finally launched into the outer 

 world quite dead. If, on the contrary, it has been 

 fertilized, its fate is very different. 



Its assured vitality transforms not only itself but 

 its surroundings. It takes a permanent station in 

 a specially prepared stopping-place, instead of 

 passing on and out to extinction. 



In the smaller mammals several egg-cells de- 

 velop at the same time, the young lying side by 

 side in a portion of the oviducts that specially en- 

 large to accommodate them ; but in the larger and 

 higher mammals this is not so. As a rule, only one 

 egg-cell develops at a time, though sometimes two 

 develop. As the egg-cell of the higher mammal 

 ripens, it leaves the ovary and passes through the 

 oviduct to where the oviducts of both sides come 

 together and enlarge, 

 forming a hollow 

 chamber, or womb. 



In the diagram is 

 represented the womb, 

 with the duct and ovary 

 of one side only, there 

 not being room to 

 show both ovaries and 



ducts. In this specially prepared womb the egg 

 may meet the sperm-cell and unite with it, if the 

 sperm-cell has been previously introduced there, 

 or it may be that the union between egg and 

 sperm -cell takes place in the oviduct, the sperm- 



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