2 CLASS MAMMALIA. 



arcades are dispersed, and elevated, to give more 

 volume and force to the muscles of their jaws. The 

 predominant sense with these animals is that of 

 smelling, and the pituitary membrane is usually- 

 extended over very numerous bony laminae. Their 

 fore-arm can turn, but with less facility than in the 

 Quadrumana, and they have no thumbs on the fore- 

 feet opposable to the other fingers. Their intestines 

 are less voluminous, in consequence of the substan- 

 tial nature of their aliments, and to avoid the putre- 

 faction that flesh must undergo if it remained for 

 any time in an elongated canal. 



In other particulars their forms and the details of 

 their organization vary considerably, and produce 

 analogous varieties in their habits to such a degree- 

 as to render it impossible to range their genera upon 

 a single scale. We are therefore obliged to divide 

 them into several families, which are variously con- 

 nected together by very numerous relations. 



THE FIRST FAMILY OF THE CARNASSIERS. 



The Cheiroptera 



Have still some affinity with the Quadrumana by 

 the pendulous penis, and the mammse situated on 

 the breast. Their distinctive character consists in 

 a fold of skin extended between their fore-feet and 

 their fingers, which sustains them in the air, and 

 even enables them to fly, when the hands are suffi- 

 ciently developed for that purpose. This arrange, 

 ment demanded powerful clavicles and large shoul- 



