in the Animal Kingdom. 



Fig. 2. 



a, J, c, d, e,f t as above. 



ff Fluid contained in the Graafian Vesicle. 



h Graafian Vesicle. 



The following table* shews how generally, the more difficult 

 to discover of these parts, have already been met with in the 

 animal kingdom. 



It is then fair to presume, since this table contains " both 

 ends," as they have been termed, of the animal world, viz. In- 

 fusoria and Man, that wherever there exists what is called a 

 perfect ovum, all the above parts are present. 



There are reasons for supposing that the Germinal Vesicle is 

 formed before the Yolk, one of which is afforded by its rela- 

 tively greater size ; + and, if so, the Germinal Vesicle, with its 

 contents, constitute the primitive portion of the ovum, which in 

 all animals, where found, appears to be essentially the same. J 



It has thus been shewn, that in all classes of animals, from 

 Infusoria to Man, germs at their origin are essentially the same 

 in character ; and that they have in common a homogeneous or 

 general structure. 



* Compiled from various sources. 



f The Germinal Vesicle is met with in those ova only, that are not quit* 

 ready for impregnation ; as it bursts on the latter taking place, and pours its 

 contents among the granules of the Germinal layer, by which it is surrounded. 



$ Purkinje, in Berlinerworterbuch, Band x. S. 111. 



