652 



MAMMALIA. 



The right ventricle is not so muscular as the left, 

 which it partly surrounds. By its contraction the blood 

 is driven into the pulmonary trunk, whose orifice is 

 guarded by three semilunar valves. During contraction 

 the tricuspid valves are pressed together, so that no re- 

 gurgitation into the right auricle can take place. 



The pulmonarytrunk divides 

 into two pulmonary arteries, 

 which branch into capillaries 

 on the walls of the lungs. 

 There the red blood corpuscles 

 gain oxygen, and the blood 

 is freed from much of the 



Fig. 286. — Circulatory system of the 

 rabbit. — In part after Parker and 

 Krause. 



(a) Letters to right — 



e.c. External carotid. 

 i.e. Internal carotid. 

 e.j. External jugular. 

 scl.a. Subclavian artery. 

 scl.v. Subclavian vein. 

 p.a. Pulmonary artery (cut short). 

 p*v. Pulmonary vein. 

 L.A. Left auricle. 

 L.V. Left ventricle. 

 d.ao. Dorsal aorta. 

 h.v. Hepatic veins. 

 c. Cceliac artery. 

 a.m. Anterior mesenteric. 

 s.r.b. Suprarenal body. 

 /. r. a. Left renal artery. 

 l.r.v. Left renal vein. 



K. Kidney. 

 p.m. Posterior mesenteric artery. 

 spm. Spermatic artery and vein. 

 c.il.a. Common iliac artery. 

 (J>) Letters to left— 



p.f. and a./. Posterior and anterior 

 facial. 

 e.j. External jugular vein. 

 i.j. Internal jugular. 

 R.Scl. Right_ subclavian artery. 

 5". V. C. Superior vena cava. 

 R.A. Right auricle. 

 R.V. Right ventricle. 

 I. V.C. Inferior vena cava. 

 r.r.a. Right renal artery. 

 r.r.v. Right renal vein. 

 s.r.b. Suprarenal body. 

 s.p.m. Spermatic artery and vein. 

 id. Ilio-lumbar vein. 

 f.v. Femoral vein. 

 i.il.v. Internal iliac veins. 



