:udied 



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 'rocess of eg 



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 1 



s more readi; 

 ' Dr. Kelson 

 'SS of egg de. 

 '^, or Roiind 

 cell-germs in 

 mediately ad- 

 ng aside all 

 :gin of these 

 Dn which we 

 itted by Dr. 

 best part 



T 







are 



further down 

 ninute nuck- 

 itute the so- 

 the remaifl- 

 :hese ani 



iniak 



ion 



ourselves o| 



.son? ^^ 



cal 



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lions' 



859' P' 



1 20' 



( 



r.^^ BEGINNINGS OF LIFE. 



201 



be understood that his opinions are in accordance with 

 those of other naturalists. 



The second stage in the 



1 



formation of the ovum has to do with the deposit of the 

 vitelUne or yolk-substance around the germinal vesicle. 



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71 





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FiG. 12. 



Early forms of ova in Ascaris mystax. (Thomson.) 

 a. Molecular condition. 



^ ■ 



h, c. Germinal vesicles becoming surrounded by yolk granules. 



d, e. Irregular forms of ova due to tight packing. 



/. Later stage showing first traces of vitelline membrane. 



Dr. Thomson says : — ^ The granules of the yolk-sub- 

 stance very soon collect round the exterior of the germi- 

 nal vesicles 1. These granules appear at first to be 



In some cases, however, the order is different. The germinal 

 vesicle may at first be surrounded by more or less of a clear viscous 

 material in which granules, after a time, make their appearance. Thus 

 Professor Thomson tells us (loc. cit. p. 133) that 'In most animals 



/ 



