RENAL PELVIS AND URETEES 



ii; 



large plate-like cells of the superficial layer. The thin transitional epi- 

 thelium of the calyces is continuous with the columnar epithelium of tin- 

 papillary ducts. 



The tunica propria, continuous with the renal interstitial tissue, 

 contains both col- 

 lagenous fibers 

 and elastic fibers. 

 It is indistinctly 

 divisible into a 

 superficial denser 

 portion, and an 

 open-meshed deep 

 portion whose fi- 

 brous bands loose- 

 ly attach the mu- 

 cous membrane to 

 the muscular coat. 

 This deep layer is 

 analogous to the 

 submucosa of the 

 alimentary tract. 



The mucous mem- 

 brane is thrown 

 into numerous 

 deep folds or rugge 

 which in the ure- 

 ter have a longi- 

 tudinal direction; 

 this condition 

 gives to the canal 

 in transverse sec- 

 tion a stellate ap- 



'..- ti 



m. ICA 



pearance Irre^u- 



- ^12. TRANSITIONAL EPITHELIUM OF DOG'S URETER. 



lar folds or inva- A, in the contracted condition; B, in the distended eon- 

 _p dition; a, basal layer of cubic colls; l>, middle layer of polyg- 



onal cells; c, superficial layer of rectangular and ovoid 

 epithelium occur cells. (R. W. Harvey, Anat. Rec., 3, 5, 1909.) X 750. 



iii the renal pelvis 



and have been described as glands, but true secreting glands are not 

 found. Occasional lymphocytes occur in the mucosa, and small lymph 

 nodules have also been found but cannot he regarded as of constant 



