VII.] SUMMARY. 231 



(2) The increase in the tail-fold. 



(3) The formation of the limbs as local thickenings 

 of the Wolffian ridge. 



(4) The formation of the olfactory grooves. 



(5) The absorption of the partition between the 

 mouth and the throat. 



(6) The vacuolation of the cells of the notochord. 



(7) The formation of the ureter. 



(8) The formation of the duct of Miiller. 



(9) The appearance of the primitive ova in the 

 germinal epithelium. 



(10) The development of a fifth pair of arterial 

 arches, and the obliteration of the first, and partial 

 obliteration of the second pair. 



(11) The development of the 'canalis auricularis,' 

 the growth of the septum of the ventricles and of the 

 auricular appendages. 



