THE URINARY SYSTEM: KIDNEYS 



437 



In the smaller of the two foetuses whose kidneys were injected (i-8 m.) the 

 arrangement of the primary capillaries from the major arcade is seen to be wholly 

 irregular. They ran in every conceivable direction, so that the festoon arrangement which 



Fi g- 34- 

 A and B. Renculi from the kidney of a Fin whale foetus 3-1 m. in length, after injection with carmine. 

 (A, x about 10; B, x about 8.) 



C and D. Renculi from the kidney of a Fin whale foetus 1-79 m. in length, after injection with carmine. 

 (Both x about 15.) 



a. Arteries of the arterial arcade. 



appears in older kidneys must be taken to represent a later development. The secondary 

 capillaries to the glomeruli were seen to be directed centripetally in these as in older 

 kidneys (Fig. 34 C, D). 



From the primary capillaries others run inwards into the medulla between the 

 uncoiled parts of the collecting tubes. They extend nearly to the papilla between the 



