THE ANATOMY OF THE INDIAN ELEPHANT. 71 



separate openings. In our dissection there was a large central 

 orifice and a smaller one on each side — one internal and the 

 other external; but the external vein was not altogether clear 

 of the central one. A thin ridge upon the internal surface of 

 the auricle separates the central from the internal orifice. The 

 veins enter a thin and membranous sinus, which is slightly- 

 separated from the rest of the auricle by a prominent fleshy 

 ridge. Part of the edge of this ridge forms the "valvular 

 structure " noted by Dr Watson. The wall of the left auricle 

 is strengthened, especially on the anterior and external sides, by 

 numerous trabeculae. The fossa ovalis is distinguishable only 

 by a slight transparency. 



Left Ventricle, : — The mitral valve forms a continuous mem- 

 branous ring, but indications of a separation into internal and 

 external cusps are visible. Vulpian and Philipeaux found only 

 two fleshy columns in the left ventricle — one above and the other 

 below. We can distinguish four or more, all nearly on the same 

 level, but divisible into an internal and external set. The 

 aortic valves are continuous with the inner mitral. 



Coronary Vessels. — Camper was probably mistaken in saying 

 that there is only one coronary artery. Like several previous 

 observers, we find two. The great coronary vein opens into the 

 left anterior cava. 



Pulmonary Artery. — Three dilatations, corresponding to the 

 sinuses of Valsalva, are distinctly visible externally. The artery 

 passes forwards, upwards, and to the left, curving round the 

 aorta and dividing in the concavity of the aortic arch into two 

 branches, one to each lung. The nearly obhterated ductus 

 arteriosus passes obliquely from right to left, from the pulmo- 

 nary artery shortly before it divides to the aorta, which it enters 

 immediately to the left of the left subclavian artery. 



Aorta. — The arch of the aorta gives off a very short innomi- 

 nate trunk, which subdivides into the right subclavian and the 

 two carotids, and secondly, a left subclavian.^ An arteria 

 thyroidea, ima proceeds from the point of separation of the two 

 carotids. 



^ Cuvier and Mayer seem to have found three trunks, viz., right subclavian, 

 carotid, and left subclavian. Hunter, Owen, Vulpian and Philipeaux, and 

 Watson agree with the statement in the text. 



