38 



G. CARL HUBER 



was necessary to reduce proportionately the thickness of the 

 wax plate representing them. As a rule, these were made about 

 one-half the thickness of the other plates. The irregularities 

 revealed by the rough model after superimposing the respect ive 

 plates, not so marked as might be supposed considering the 

 thickness of the plates used, were adjusted, not by trimming 

 the model and cutting away wax, but by smoothing with warm 

 irons. The possibility of error is admitted, but since all of the 

 models were made in the same way, errors if committed were 

 probably essentially the same for all of the models. The volumes 

 of the models were obtained by weighing the water displaced 

 by each, and after making the necessary temperature corrections, 

 reducing weight of water displaced to volume. The average 

 of several determinations is given in table 4. 



TAB I E I 



The uniformity of the figures giving the actual volume of the 

 egg mass, as determined by the weight of the water displaced 

 by the models of the respective ova reconstructed, leads me to 

 feel that the errors committed in reconstruction were not serious. 

 The last column of the table, giving averages, is of interest 

 since it shows a very slight increase in the volume of the egg- 

 mass during segmentation and transit through the oviduct. 

 Following the pronuclear stage, which, as has been seen, ex- 



