*S4 ^^^ ^' Home's Additions to an Account 



circular canals are contained, the canals themselves not being 

 much larger than in the skate. They are shewn in the draw- 

 ing. In the recent subject they were pellucid, containing a 

 transparent fluid. 



On the Structure of the Branchial Artery. 



The muscular structure of the branchial artery of the dog- 

 fish, and the direction in which that artery leaves the ven- 

 tricle, are exactly the same as in the Squalus Maximus, only 

 are seen upon so small a scale, that they do not arrest our 

 attention ; but when magnified, to the size which they acquire 

 in this fish, they make a stronger impression on the mind, and 

 force us irresistibly to enquire into their use. 



This direction of the artery appears to be common to fishes 

 in general ; but the muscular structure is confined to particu- 

 lar tribes. I find it is common to all the sharks, and there is 

 a similar structure in the sturgeon. 



In the wolf fish, the Anarchichus Lupus, the muscular struc- 

 ture of the branchial artery is nearly the same; but the valves 

 are placed close to the opening of the ventricle, and are only 

 two in number. 



In the turbot there is no muscular structure in this part of 

 the artery ; but the coats are extremely elastic, and admit of 

 being very considerably dilated, particularly at its origin, where 

 three valves are placed, and so contrived that the dilatation 

 of the artery makes them shut more closely. 



In the Lophius Piscatorius, there is no appearance of mus- 

 cularity in the coats of the branchial artery, and no lateral 

 valves as in other fishes ; but there is a muscular tube half 



