EXPLANATION OF THE PLATES. 



PLATE LVIII. 



Fig. 1. Tubes of the kidney, showing their general character, 

 and but slightly magnified. 



Fig. 2. Cross section of the elastic framework in which both 

 the secreting tubes and the Malpighian bodies are 

 enclosed. 



Fig. 3. Cross section of both the elastic framework and the 

 secreting tubes themselves. 



Fig. 4. Oblique section of the veins contained in the tubular 

 part of the kidney, showing their arrangement in 

 sets. 



Fig. 5. The same vessels seen lengthways. 



Fig. 6. Secreting tubes of the kidney, in different condi- 

 tions : in one the cells are seen to form a regular 

 pavement epithelium ; in a second the central canal, 

 along which the urine, secreted by the Malpighian 

 bodies and cells of the tubes, flows, is shown ; in 

 a third the cells are irregularly disposed, and this is 

 generally found to be the case in the tubes of the 

 central part of the kidney, and when the kidney 

 is not perfectly fresh; in a fourth there are no 

 secreting cells, and the structureless basement 

 membrane of the tubes alone remains. 



