636 



OF SECRETION. 



Fig. 246. 



z-. 



A small portion of the Kidney, magnified about 60 times; 1, supposed ccecal extremity "of a tubulu* 

 uriniferus ; 3, 3, recurrent loops of tubuli ; 5, 5, bifurcations of tubuli ; 4, 5, 6, tubuli converging towards 

 the papilla ; 7, 7, 7, Corpora Malpighiana, seen to consist of plexuses of blood-vessels, connected with a 

 capillary net-work ; 8, arterial trunk. 



c. The Embryological Development of the Urinary organs in Vertebrated animals is a 

 subject of peculiar interest; owing to the correspondence which may be traced between the 

 transitory forms they present in the higher classes, and their permanent condition in the 

 lower. In this respect there is an evident analogy with the Respiratory system. The first 



