336 THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC. 



of the kidney are usually more or less coloured with a golden- 

 yellow pigment. According- to Tornier it bears short cilia (Fig-. 

 218 XIV). 



The third portion corresponds with the narrow limb of Henle's 

 loop; it is lined with ciliated epithelium (Fig*. 218 VIII, b to <), 

 similar to that in the neck of the tube. 



The fourth portion (Fig. 218 VIII, c to d, and XIII) repre- 

 sents the wider limb of HemVs loop. It has a winding 1 course 

 in the ventral part of the kidney, and then ascends dorsally to 

 open into a collecting-tube. The fourth part of the tube is lined 

 with a short, columnar epithelium (Fig. 218 VIII, c to d], which 

 has a clear, cuticular, free border, large nucleus, and a peculiar 

 arrangement of the protoplasm, which shows a rod-like structure 

 (Fig. 218 XI). 



The collecting-tubes course transversely near the dorsal surface 

 of the kidney (Fig. 217), and the uriniferous tubes meet them at 

 right-angles. They are lined with a short polygonal epithelium 

 (Fig. 218 VII). 



The peritoneal funnels of the kidney (nephrostomes). Spengel, Meyer, and 

 Hoffmann describe these funnels as existing in the frog; according to them they 

 open on the ventral surface by narrow apertures, and each is connected, by a vertical 

 tubule, with the fourth part of the uriniferous tube (Spengel), but according to 

 Nussbaum, with the neck of the tube. According to Spengel and Meyer the number 

 of these funnels is in Eana from 250 to 360. 



According to Wiedersheim the funnels hang free from the ventral surface like so 

 many parasites attached by fine filaments, and do not open on the surface. 



Heidenhain (Arch. f. inik. Anat., Vol. X) was unable to find these organs. 



Being unable to find any trace of these organs in the kidneys of either R. tempo- 

 raria or R. esculenta, in microscopic sections or in teased preparations, I inserted 

 canulae into the ureters of both male and female specimens of both species, and 

 injected the uriniferous tubes with a solution of Berlin blue. Although the tubules 

 were, in some cases, completely injected, in no case could I find any trace of a 

 peritoneal funnel, nor was there any escape of the solution from the kidney as would 

 be the case if the funnels were open and communicated with any part of the uri- 

 niferous tubes. Even when the pressure was increased to the extent of a column 

 of 25 cm. high of the injection-mass, no escape took place from the surface of the 

 kidney, though in numerous cases the uriniferous tubes were ruptured by the abnor- 

 mally high pressure. 



Properly dissected frogs were placed in 0-6 / sodium chloride solution, in which 

 finely divided gamboge was suspended. No trace of ciliary action was, in any case, 

 found on either surface of the kidneys. 



One may therefore conclude that if the peritoneal funnels exist in the adult frog 

 (i) they are veiy difficult to find; (2) they do not form a free communicating path 

 between any part of the uriniferous tubes and the abdominal cavity ; (3) their 

 superficial terminations have no free cilia. As before stated I have found no 

 trace of any such organs. 



