438 



COMPARATIVE ANATOMY 



NEPHROGENIC ':*»; 

 TISSUE ~'^. 



ANLAGE OF " 

 EXCRETORY- 

 TUBULE (■■■>( 



COLLECTING TUBULE- 



B. 



COLLECTING^ 

 TUBULE 



:.:m^ -■ --' 



r^NEPHROGENIC TISSUE— ^lai 



ANLAGE OF EXCRETORY ^r^-r 

 -^ TUBULE " ' 



;r COLLECTING TUBULE- 

 ' ^^ GLOMERULUS'^ 



■J-- EXCRETORY TUBULE-, 



Fig. 365. — Diagrams A-E illustrating the development of collecting and secretory 

 tubules of the kidney. Vesicles derived from nephrogenic tissue become attached to the 

 collecting tubules and thus functionally connected with them. The swollen termination 

 of each secretory tubule encloses a glomerukis and forms a renal corpuscle. E repre- 

 sents an earlier, D a later stage of development. (Redrawn after Coming's " Hiunan 

 Embryology.") , 



■ARCH OF COLLECTING 

 TUBULE 



NAL CORF=USCLE 



ARCH OF COLLECTING 

 TUBULE 



distal convoluted tub. 

 ■stdcrck's loop, 

 proximal convoluted 



TUBULE 



GLOMERULUS 

 BCWMAN's CAPSULE 



0ESCEh40ING LIMB 



GLOMERULUS 



B- ^ STOERCK'S UDOP 



Fig. 366. — Diagrams of three stages A-C in the growth and differentiation of a 



uriniferous tubule. The collecting tubule is shown unshaded, 

 after Huber and Stoerck.) 



(Redrawn from Arey, 



