ss8 Sir E. Home's Additions to an Account 



to enter into minutise, but to render my former account more 

 complete, and apply the dissection of this large fish to its proper 

 use in comparative anatomy, which is, by means of it, to illus- 

 trate the functions of the organs of fishes of an ordinary size. 



In addition to my former description of the fins, I have now 

 annexed a drawing (PI. XVI.) which shews the structure of 

 the pectoral fin, a beautiful example of the mechanism of the 

 fins of cartilaginous fishes in general. 



The stomach was examined in its entire state, and the an- 

 nexed drawing (PI. XVII.) is an accurate representation of 

 the appearance of its internal surface, which is exposed in one 

 view, shewing that the pyloric portion is longer and narrower 

 than I had before represented it. 



The situation of the pancreas is correctly noticed in my 

 former paper ; the gland is oblong, thick and round where it 

 is attached to the duodenum, and becoming thin, flat, and bifid 

 towards its loose extremity. 



The ducts of the liver are six in number, and inclosed in a 

 broad flat band, which passes obliquely down before the sto- 

 mach, till it is connected to the duodenum ; each of the ducts 

 opens, by a separate oblique orifice, into a common cavity of 

 an oval form, from which there is a direct opening into the 

 duodenum. This swell or enlargement might be considered 

 as a substitute for the gall-bladder, which is wanting, were it 

 not that a similar enlargement is also met with in fishes which 

 have one. In the cod there is the same dilatation, and the 

 hepatic ducts open into it in the same oblique manner ; but 

 there is also a gall-bladder, and the cystic duct, as well as the 

 others, terminates in this dilatation. 



The oblique openings of the hepatic ducts in the Squalus 



