PHYSIOLOGY : PRACTICUM V : PLATE XIII. 

 HEART OF THE SHEEP, THE RIGHT AURICLE OPENED ; X .8. 



bronchus 

 lung 



AZYGOUS VEIN 

 pericardial line 



POSTCAVA 



CORONARY 



SINUS 



- PRECAVA 

 pericardial line 



- base of precava 



- pulmonary artery 





The preparation ( 2785 ) is viewed from the right side and obliquely, the apex away, so 

 that the INTERVENTRICULAR FURROW, PI. XII, does not appear. 



The right wall of the PRECAVA has been wholly removed, but that of the AURICLE 

 is turned caudad upon the VENTRICLE so as to expose the TRABECUL^E and interven- 

 ing SINUSES which characterize the ventral or APPENDICAL part. 



The AORTA (A] and its principal branch (B) have appeared in PI. XII and from 

 different aspects. The vessel marked PULMONARY ARTERY looks at first as if it were 

 continuous with the aorta. The CONUS is the part of the right ventricle from which the 

 PULMONARY ARTERY directly arises. 



At the left of the figure the interrupted line from the upper (cephalic) margin of the 

 postcava indicates its course into the atrium. The FOSSA OVALIS is within the orifice of 

 the postcava; strictly speaking, what is here apparently an orifice of the postcava should 

 be regarded as part of the atrium itself ; notwithstanding the description by Morrell and 

 the observations embodied in several theses for graduation at Cornell University there are 

 many points of comparison between the hearts of man and sheep that have not been made 

 satisfactorily. 



i , ridge at the junction of the PRECAVA. 2, transection of a prominent TRABECULA 

 of the APPENDICAL PART of the AURICLE. 3, ectal surface of APPENDIX. 4, termi- 

 nation of cut of wall. 5, trabecula. 6, smooth ental surface of ATRIUM. 7, valve be- 

 tween POSTCAVA and CORONARY SINUS. 9, TUBERCLE OF LOWER between post- 

 cava and precava. 



