ORDER CARNASSIER. 135 



to what extent it pleases. But, as may well be imagined, 

 the nycteres convey air into these vessels, by virtue of a pe- 

 culiar mechanism, and by means of an organization, which 

 with all its anomalies, is still derived from the primordial 

 type of the class to which they belong. 



The results of so new a mode of organization are, un- 

 questionably, worthy of research. The means which pro- 

 duce it are perfectly simple. 



The skin has no adherence to the body, except in some 

 places where it is retained by a celular texture, very flaccid, 

 and separated. The air is introduced through this, and 

 remaining between the skin and flesh, gives to the animal 

 that appearance which is observed in veal when blown up 

 in the butcher's shops. There are none of those threads, 

 or cellular tissue, to be found, except in the neighbour- 

 hood of the conduits, and on the sides of the thumb. Thus, 

 the skin is completely raised on the back, the chest, and 

 the abdomen. The nycteres are thus immersed in a bath 

 of air, or rather placed in a sort of muff, which this elastic 

 fluid forms around them. 



However extraordinary, such a fact as we have been 

 describing, may seem, it yet appears to detract nothing 

 from the essential character of the mammiferous type. 

 Nor is this essential character any more affected by the 

 mode in which this singular and extensive cellular system 

 is inflated. 



At the bottom of each cheek-pouch is found a small aper- 

 ture, and it is simply by means of this, that the aerial sac 

 communicates with the mouth. The animal, in opening 

 its nasal cavities, causes the circumambient air to enter 

 and inflate its chest. On the other hand, in a moment 

 after, by^abandoning the nasal membranes to their natural 

 elasticity, and, at the same time, keeping the mouth closely 

 shut, it forces the gas, which has been respired, to return 

 into the cheek-pouches, and thence into the large aerial sac. 



