8 PISCES. 



called the termination of the whole system, is very 

 small in proportion to the net-work from which it 

 rises ; and indeed the lymphatics of the part are so 

 large as to exceed by far the size of the sanguiferous 

 vessels. 



The thoracic duct from the left side, having 

 passed under the oesophagus from the right, runs 

 on the inside of the vena cava of the left side, re- 

 ceives a branch from its fellow of the opposite side, 

 and joins the large lymphatics which lie on the left 

 side of the pericardium, and a part of those which 

 lie behind the heart, and afterwards makes, together 

 with the lymphatics from the gills, upper fins, and 

 side of the fish, a network, from which a vessel 

 passes into the jugular vein of this side : in a word, 

 the lymphatics of the left side agree exactly with 

 those of the right. Another part of the system is 

 more deeply seated, lying between the roots of the 

 spinal processes of the back-bone. This part consists 

 of a large trunk that begins from the lower part of 

 the fish, and as it ascends receives branches from 

 the dorsal fins and adjacent parts of the body: it 

 goes up near the head, and sends a branch to each 

 thoracic duct near its origin, 



The brain in fishes is formed pretty much in the 

 same way as in fowls ; only we may observe that 

 the posterior lobes bear a greater proportion to the 

 anterior. 



The organ of smelling is large, and the animals 

 have a power of contracting and dilating the entry 

 to it as they have occasion : it seems to be mostly 

 by their acute smell that they discover their food, 



