202 



THE CAT. 



[chap. VII. 



Tlie whole inner wall of the heart is lined with a layer of 

 endothelium, which immediately invests a network of elastic fibres. 



Fi". 103.— DlAORAM OF THE COURSE OF THE CiRCCLATION, SEr.N DORSALLY. 



An. Arteries to aliini'iitiuy tube. 



AK Arteries to anterior iiarts of botly and fore- 



liiiilis. 

 AK Arteries to liimler parts of body aiulhiud- 



liiiilis. 

 Al. Alimentary tube. 

 All. Aorta, 

 y/rt. Hepatic arterj-. 

 ]Ir. Hejiatic vein. 

 LH. Laeteals. 



I:]. LlUIKS. 



lA. heft auriele. 



Lr. Liver. 



IV. Left ventricle 



ly. Lyniiiliaties. 



I ]'A. Pulmonary artery. 



PF. Pulmoniirv vein. 



]!A. Hi-lit auricle. 



7.' J'. l{i-lit ventricle. 



'/'. Tlioracic duct. 



I 'I. Vcin.s from anterior iiarts of body and fore- 

 limbs. 



VK \'eins from posterior part of botlj- and hind- 

 lind>s. 



TCI. Vena cava inferior. 



TT.S'. Vena cava superior. 



VI'. Vena porta. 



The vessels wliicli carry venou."! blood are dis- 

 tinttuislicd by sliadin;;. Arrows indie. te tlic 

 couree of tlie bluoil-lymph and chyle. 



Thus the substance of the heart shows a similarity of structure to 

 that of the vcs.'^els Avhich might be expected, since its walls are 



