THE URINARY ORGANS. 337 



The lobules of the kidney. When treated with proper reagents 

 the kidney shows a marked tendency to separate into lobules (Fig. 

 219 I). 



The lymphatics of the kidney (Fig. 216 III l ) form an irregular 

 network of fine canals with elongated meshes. They run chiefly 

 in the direction of the blood-vessels. The large vessels, which 

 supply the kidney, are surrounded by large lymphatics.] 



The nerves of the kidney (Fig. 219 II) 1 . Little is known of 

 these. Xerve-fibres have been traced alongside the larger blood- 

 -1 through the greater part of the kidney. 



B. The ureters. 



a. General description. In the males the ureters are, at the 

 same time, the seminiferous ducts. Each ureter commences on the 

 dorsal surface of the kidney by bifurcating branches, which are 

 continuous with the collecting-tubes of the kidney. In the anterior 

 two-thirds of the kidney the ureter is wholly on the dorsal surface ; 

 at the junction of the middle and posterior thirds it winds round to 

 the outer border of the kidney (Fig. 214 l~r), and there lies in a 

 groove accompanied by the renal portal vein (Fig. 220 I r and la), 

 the two organs being intimately attached to the kidney substance 

 and enclosed by the fibrous capsule (Bg). 



This portion of the ureter possesses a spindle-shaped enlargement, 

 which represents the Rcceptacttium xtiiiinis. In Jiana tempontria the 

 Receptacnhim seminls forms a large saccular dilatation. 



In its further course the ureter runs backwards and slightly 

 inwards, converging with its fellow of the opposite side ; the ureters 

 lie free in the abdominal cavity, and terminate by two openings 

 placed side by side in a groove on the dorsal wall of the cloaca 



In females the ureters are intimately attached to the dilated 

 oviduct, immediately after leaving the kidney; they pursue a 

 similar course to those of the males, but are attached to the oviduct 

 in the whole of their course to the cloaca. 



b. Minute structure. The ureter is a tube composed of connective- 



1 See Plate II. 

 Two portions from a gold preparation of the kidney of Rana aculfnla. G. H. 



I. Showing the tendency t<j split into lobules. 

 II. Nerve-fibres accompanying the blood-vessels. 

 a Blood-vessels. 

 I Nerves. 



Z 



