XXII.] STEUCTUBE OF THE KIDNEY, 231 



sometimes imbricated, with striated outer 

 portions and containing oval nuclei ; the 

 lumen is small. 



S. The descending limbs of the loops; 

 these are much narrower, with trans- 

 parent flattened epithelium the nuclei 

 of which project into the lumen, some- 

 times alternately on the two sides, and 

 thus the tube, except for its basement 

 membrane, simulates a blood capillary. 



■ The change in character of the epithelium 

 may take place either in the ascending or in 

 the descending limb of the loop. 



e. The numerous blood-vessels between the 

 medullary rays (cp. § 8, 6) ; in the outer 

 part of the layer rather large arteries 

 and veins cut transversely or obliquely 

 will be seen (cp. § 1, c). 



c. In the cortex 



a. The end-capsules, with the nuclei of 

 their epithehum. 



/3. The glomerulus in each end-capsule 

 (cp. § 8, c) and the nuclei of its capillaries. 



ry. The narrow neck of the capsule, this 

 will be obvious in those capsules only 

 in which the section has passed longi- 

 tudinally through the neck. 



S. The coiled course of the convoluted 

 tubes (tubuli contorti); the outlines of 



