44 COMPARATIVE ANATOMY 



is truly striking. The sketches a and J, in Plate I., 

 exhibit this paw in one of the herbivorous and in 

 one of the ordinary Cetacea, when covered with 

 their usual integuments, and c and d exhibit the 

 same part when deprived of these appurtenances; 

 both of these can easily be compared with the 

 human arm, 0, and the simple unity of their struc- 

 ture, and the peculiar adaptation of each to its 

 function, will, after this survey, scarcely require 

 farther demonstration. We supply a sketch of the 

 same part in the great whale of Greenland ; and it 

 is striking to observe, how much even this great fin 

 supplies a representation of the osteology of the arm 

 in man. And as with the anterior extremities, so 



it is with the posterior or sacral. In the whole 

 Cetacea they become wholly rudimental, and leave 

 scarcely a trace behind. The progress of the change, 

 as seen externally, which we exhibit through three 

 successive links of the animal series, is beautiful 

 and interesting ; sketch / shows them in the am- 

 phibias the seal; sketch g^ in the herbivorous 

 Cetacea the Dugong of the East Indies; and 



