Mil 



ZOOLOGY. 



appendages (Fig. 446), named, indifferently, arms or 11- 

 which merit equally both names, for they are at once tin- 

 instruments of prehension and of locomotion. 



Fig. 416. Common Calmar (the Loligo 

 Sagittarius) . 



599. The cephalopoda are essential!} 7 aquatic animals, 

 and they in consequence breathe by gills. These organs are 



Fig. 417. Gills of the Poulpe (Octopus).* 



found concealed in the mantle, under a particular cavity (Fig. 

 I 17 1, whose walls dilate and contract alternately, and whose 



" * The body of an Octopus, as seen on its inferior surface (the mantle is 

 Uid open in the median line and on one side, and is turned outwards t<> 

 show the interior of the respiratory i-:nity) : </, l>as> of tin- licn.l : /, tin- 

 tulx-liy which tut- water leaves the respirati>r\ r.-ivity : '..one of the two 



lateral opening* for which &e water penetrate* into this cavity; f>, one of 



tJi- lininchiii- <>r L'ilK. 



