G. Carl Hiiber 



69 



descending limbs) inoasuring .?:> mni. The length of tubule B is 5 niiii., 

 of this 2.65 mm. falls to the proximal convoluted portion and 1.5 mm., 

 to the entire loop of Henle. In these tubules, as is no doubt apparent 

 from the figures and measurements given, the proximal convoluted por- 



FiG. 16. Two uriniferoiis tubules, A, from kidney of cat embryo of 4 cm. 

 length (No. 6); B. from kidney of cat embryo of 6 cm. length (No. 8). 

 X 100. A', B', figures showing the course of the proximal and distal con- 

 voluted portions of the two tubules; the tubule representing the distal con- 

 voluted portion is shaded; m', Malpighian corpuscles. 



tions form the more prominent part, a little over half the length of the 

 entire tubule. Similar observations may be made on the kidneys of 

 human embryos of about the third and fourth month; although the 

 diflPerences of size and shape of the tubules which develop first when com- 

 pared with those which develop later are not so marked in the human 



