FERTILISATION 



193 



place at the end of the first minute after the addition of the sperm to 

 the eggs, we get even more striking figures. The oxygen consumption 



FIG. 60. The insemination of the eggs of Saccocirrus while these are under- 

 going growth in the ovarian tissue. The long black rod -like body in the 

 cytoplasm of the primitive ovocytes is the spermatozoon. It will be 

 seen that the ovum develops from a very early stage with the spermatozoon 

 in its cytoplasm, actual fusion of sperm and female pronucleus only taking 

 place after the eggs are laid and have undergone meiosis. (From Buchner's 

 Praktikum far Zrtlenlehre, Bd. i., Borntraeger.) 



of the unfertilised egg is so low, however, that its measurement for 

 so short a time is difficult with the quantity of eggs usually employed 

 ( to 1 million eggs) in an experiment, as usually no reading can 



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