The development of tlie kidney in tlic rabbit. 



2itl 



cut across. In tlie subsequent sections the vesicles will be seen to 

 disappear, to pass into tubules which join together and become con- 

 tinuous with the ureter, before which however they are joined by two 

 other tubules (in h and i). 



Fig. 6. 



A series of sections through the lower half of the Kidney of a 



12 days embryo rabbit, shewing from a to i the passage of two 



renal vesicles into tubules and finally into the Ureter. 



Embryo Rabbit of thirteen days. 

 My next embryo is one of the 13tli day and the Kidney measures 

 0,041 cm across. The ureter is seen to divide into three main 

 branches and these into six or seven. These do not end in the com- 

 pressed spherical vesicles seen in the embryo of 12 days, for these 



19* 



