SECRETION OF URINE. 



Fig. 154. 



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A small portion of the Kidney, magnified about 60 times; 1, supposed coecal extremity of a tubulus 

 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. (After Wagner.) 



cloaca. Between their component shut sacs, numbers of small points appear, which 

 consist of little clusters of con voluted vessels,exactly analogous to the Corpora Malpighiana 

 of the kidney. The Corpora Wolffiana, however, have only a temporary existence in the 

 higher Vertebrata; although it seems that, in Fishes, they constitute the permanent kid- 

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