508 



ZOOLOGY. 



mouth occupies the middle, and is armed with two jaws. 

 Finally, around this opening is a corona of flexible fleshy 

 appendages (Fig. 532), named, indifferently, arms or feet, and 



Fig. 532. Common Calmar (the Loligo Sagittarius) ; 

 a Cuttle Fish. 



which merit equally both names, for they are at once the 

 instruments of prehension and of locomotion. 



Fig. 533. Gills of the Poulpe (Octopus) ; 

 Sepia, or Cuttle Fish.* 



599. The cephalopoda are essentially aquatic animals, 

 and they in consequence breathe by gills. These organs are 



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

 laid open in the median line and on one side, and is turned outwards to show 

 the interior of the respiratory cavity) : a, base of the head ; i, the tube by 

 which the water leaves the respiratory cavity ; o, one of the two lateral 

 openings by which the water penetrates into this cavity ; b, one of the bran- 

 chiae, or gills. 



