The pronephros of Chrysemys marginata. 79 



tertiary, etc. niesoiiephric tubules. The region of the nephrotome into 

 which each mesonephric tubule opens becomes enlarged to form a 

 malpighian capsule. 



9. The vascular supply to the anterior region of the kidney is 

 in the form of a continuous outgrowth from the aorta, and this 

 projects as a glomus into the coelom. The rotation and metamerism 

 aifect the glomus in the posterior part of the pronephros and in the 

 anterior part of the mesonephros, and so the glomus in these regions 

 is represented subdivided into glomeruli. The blood-supply develops 

 after the tubule-formation. 



10. Later modification of the mesonephric growth consists in the 

 branching of the primary glomeruli; fusion in places of vascular 

 tissue with the nephrotomic wall between the tubule nephrostomes 

 leads to the subdivision of the nephrotome into Malpighian capsules, 

 and so to an increase in the number of Malpighian capsules with 

 glomeruli and nephrostomes. 



