94 TJARNIVORA. 



end, and become gradually thinner downwards : they describe a circle 

 when in their most natural state ; but are capable of being made much 

 more straight. 



The pericardium is some way from the diaphragm, between which 

 parts there is a bag. This is made up of the pericardium forwards or 

 above, the diaphragm being opposite to it ; and of two very thin mem- 

 branes laterally : these last are so loose as to allow of a large distension 

 of this bag, and will likewise admit of the apex of the pericardium (if 

 I may so call it) touching the side of the diaphragm ; but it will not allow 

 the basis, for that is tied on one side by the vena cava inferior ; and on 

 the other side the membrane becomes not so loose, and stronger, so as 

 to be only stretched between them. The mouth of this bag is on the 

 right between the vena cava and the back. 



The lung of the right side is divided into three lobes, besides the lobe 

 that is situated in the above-mentioned bag ; which lobe is a continua- 

 tion of the right lung, and is something like the lobulus Spigelii of the 

 liver. On the left side the lung is divided into two lobes only. 



The distance between the diaphragm and the upper part of the thorax 

 is greater than in the human, which is the reason that the heart is at so 

 great a distance from either, and is the reason why the superior and 

 inferior venae cavas are so long ; likewise the carotid arteries, for the 

 curve of the aorta is as near the heart as in the human. This increase 

 of length in the thorax is to increase the size of the lungs, to make up 

 for the smallness or narrowness of the chest in quadrupeds. 



The oesophagus is pretty nearly of an equal size through its whole 

 length, and has a capside between the heart and the diaphragm ; which 

 capsule has the lower two lobes of the lungs of each side adhering to it 

 by broad membranes. 



The eyelids have both a raiser and depressor : the depressor is a very 

 thin muscle coming from the bottom of the orbit. The membrana 

 nictitans is of a darkish colour, and differs very little from those of 

 other animals ; it has part of the depressor muscle of the under eyelid 

 inserted into it. There is one punetum lacrymale, which is on the inner 

 side of the under eyelid, a little way on the inside of its edge. The 

 edges of the eyelids are of a darkish colour all round. The trochlea of 

 the trochlearius muscle is not close to the orbit, as in the human sub- 

 ject. The orbit is different at its upper end and other parts, through 

 its whole length, and is of considerable breadth. This place or notch is 

 filled up with a muscle and ligament, but this muscle does not arise from 

 the edge of the bone, but from the lower surface of the orbit by a thin 

 origin nearly the whole depth of the orbit, and passing outwards round 

 all the muscles and fat of the eyeball, it is inserted into an elastic 



