74 



SCIENCE PRIMERS, 



[§v. 



Fig. II. — Left Side of the Heart of a Sheep (laid open). 



P. V. pulmonary veins opening into the left auricle by four openings, as 

 shown by the styles or pieces of whalebone placed in them : a, a style passed 

 from auricle Into ventricle through the auriculo-ventricular orifice ; b, a style 

 passed irto tne coionary /ein, ^«; ich, though it haf no connection with the 

 left auricle, is, from its pos'ti^n, recessarily cut across in thus laying open the 

 auricle. 



M.V. the two ilaps of the mitral valve (drawn somewhat Jiagrammati- 

 cally) : pp. papillary muscle?, be'onging as before to the part of the ventricle 

 cut away ; c, a style passed from ventricle in Ao. aorta ; Ao^. branch of 

 aorta (see Fig. 5, A' d , ', P,A. pulmonary artery; S.V.C superior vena 

 cava. 



T, wall of ventricle cut across; 2, wall of auricle cut .. -vay "around auriculo- 

 ventri' ular o-ifice ; 3, other portions of auricular wall cut across ; 4, mass of 

 fat around base of ventricle (see Fig. 5, 2). 



