# INTRODUCTION. 



in each, the same respective situation ; but the modification of the bones 

 of the skull, vertebral column, and organs of locomotion, is greatly 

 varied : in the fish, indeed, the bones of the cranium, in particular, 

 present what, in reference to Mammalia, may be termed an elementary 

 condition. 



10 



11 



Of the above figures, 8 is the skeleton of the Lemur ; 9, that of the 

 Eagle ; 10, that of the Alligator ; 11, that of the Carp. In all the above 

 examples of the vertebrata, the essentials of the osseous framework are 

 present : it is easy, however, to see how the extremities are modified in 

 each ; and how, from the almost human Jimbs of the Lemur, they merge 

 into the swimming organs of the fish ; the modification of the ribs and 

 sternum is, also, no less remarkable. 



The importance attached to the structure of the osseous framework 

 of the Mammalia, as conducive to a correct knowledge and just ap- 

 preciation of the various groups of which the class consists, has been 

 acknowledged by all naturalists, and will be a sufficient justification 



