40 



THE NATURAL HISTORY OF 



we may conclude that these animals have thus a percep- 

 tion, even at a great distance, of odoriferous bodies. 



THE PECTORAL AND DORSAL FINS. 



The fins are placed on each side, and contain bones 

 similar to the anterior extremity of the digitated animals, 

 inasmuch as there are bones corresponding to the arm, 

 fore-arm, carpus or wrist, and a series of phalanges, 

 which are enveloped within a strong condensed adipose 

 membrane of a semi-cartilaginous consistence.* 



Some of the other species (which I shall hereafter 

 describe) have a dorsal fin, the forms of which greatly 

 differ, and which is situated either at a greater or less 

 distance from the orifice of the spiracles, or from the ex- 

 tremity of the tail. The common and Iceland whales 

 have no such thing. 



CONSTRUCTION OF THE TAIL.t 



The manner in which this tremendous and only 

 weapon of defence belonging to this animal is con- 

 structed is, perhaps, as beautiful as to its mechanism 

 as any other part of the animal: it is wholly composed 

 of three layers of tendinous fibres, covered by the com- 



* The description of the skeleton of the Baleenoptera R6rqual, or broad- 

 nosed whale, which will be found in its proper place, will give the reader 

 some idea of the formation of the skeletons of the Cetacea generally. 



t The above engraving represents a specimen which was twenty feet, 

 five inches in breadth, in a whale fifty-three feet long. 



