1898.] 



SYSTEM OF THE CHIBOPTEEA. 



63 



to the pericardium, and the azygos lobe of the right lung crosses 

 similarly on the dorsal side, lying immediately behind the left 

 auricle and ventricle. 



rig- 1. 



fu L5.\* 



Heart and lungs of Pteropiis medius, seen from tlie ventral aspect. X Ij. Tlie 

 blood-vessels are slightly diagrammatic; the exact position is seen in fig. 4 

 (p. 66), which is from a photograph. The anterior lobe of the left lung is 

 raised slightly to show the conns arteriosus. 



R.S. Eight Subclavian artery. T.A. Thyroid Axis. E.0.0. Right 

 Common Carotid. R.V. Vertebral. L.I.M. Left Internal Manimarv. 

 E.P.C. Eight Precaval Vein. L.S.V. Left Subclavian Vein. L.I.J. Lett 

 Internal Jugular. L.E.J. Left External Jugular. V.V. Left Vertebral. 

 P.C. is placed on the middle lobe of the right lung just above the Post- 

 caval Vein. T. Trachea. EA., EM., EP. Anterior, middle, and posterior 

 lobes of the right lung. AZ. Azygo.s lobe. LA., LP. Anterior and 

 posterior lobes of the left lung. 



The Pericardium. 



A very definite sac, composed of two layers — a fibro-serous, form- 

 ing an envelope for the heart and great vessels, and a serous, 

 reliected on to the surface of those structures. 



The libro-serous layer encloses a space, the shape of which is 



