50 



Development and Shape of Uriniferous Tubules 



tubules first developed must then traverse the greater part of the cortex, 

 so far as developed, in order to reach the peripheral ends of the collecting 

 tubules. (See Stoerk, page 304.) 



A detailed description of the several models, on which is based the account 

 here given of the early developmental stages of uriniferous tubules, is 



Fig. 8. Semidiagrammatic figures of the anlage and differentiation of renal 

 vesicles and early developmental stages of uriniferous tubules of mammals. 

 1 and 2, anlage and successive stages in the differentiation of renal vesicles, 

 as seen in sagittal sections; 3, section and outer form of tubular anlage before 

 union with collecting tubule at the beginning of S-shaped stage; 4 and 5, 

 successive stages in the development of the tubules, Bowman's capsule and 

 glomerulus beginning with a tubular anlage showing a well developed S-shape. 



obviated, it seems to me, b,y the number of illustrations of these stages 

 here presented. My own observations and the conclusions reached con- 

 cerning the anlage and early developmental stages of the uriniferous 

 tubules and the genesis of the different parts of these tubules I have 

 summarized by way of a series of diagrammatic figures grouped under 

 Fig. 8. 



