60 



ESSENTIALS OF ZOOLOGY 



g. The Excretory or Urinary Syste7n is made up of tubular struc- 

 tures and accessory parts, such as flame cells, nephridia, Malpighian 

 tubules, green glands, and kidneys. In the mammals, the ureters, 

 urinary bladder, and urethra are accessory to the kidneys. The kid- 



.duqudarVm 

 .Carotid ArUry 



.JTrachca 



...SiibclcLvianV. 

 PrecavalV. 



Oorsoil Aorta 



Pulmonary A. 



Left Aun'cfe 



LeftVcntr/d2 



Luna 



Diaphracfm 



1 Livcp 



Uiiodaniim 



.. .Stomach 



Jtunivcrse C.Q\on 



Dcicendlnc] Co/on 

 Aiccndm^ Colon 



Ileum 



Fig. 16. — Human manikin showing parts of the principal systems from ventral 



view. (Drawn by Edward O'Malley.) 



neys withdraw liquid waste products of metabolism from the blood 

 and deliver them to the outside of the body. The nitrogenous sub- 

 stances, urea and uric acid dissolved in water, are the principal prod- 

 ucts discharged. 



