162 BREATHING APPARATUS. 



alarmed, than they sink to the bottom of the sea, and 

 there throw out from the funnel a stream of ink, which, 

 like a black cloud, enshrouds them in welcome darkness, 

 concealing them from the gaze of their foe. It is some 

 time before the opaque and murky cloud dissipates : 

 if the danger be passed, they recommence their ac- 

 tivity in search of prey ; if not, they pour out another 

 volume of ink, and remain quiet, enveloped in its 

 shelter. 



Allusion has already been made to the branchise of 

 the cephalopods, or, in other words, to their breathing 

 apparatus. As these animals are organised for the res- 

 piration of water, not of air, we find in a distinct cham- 

 ber on each side of the body, separated from the viscera 

 by a membraneous partition, a beautiful aerating or bran- 

 chial apparatus, consisting of a single stem, with foliated 

 appendages, excepting in the nautilus, which has a double 

 gill, or two stems with their fringe-like or foliated ap- 

 pendages, in each lateral cavity. These appendages 

 are exquisitely vascular, and the blood circulating 

 through the inconceivably minute vessels, is there sub- 

 jected to the action of the oxygen. Into each chamber 

 or branchial cavity the water is admitted through a 

 valvular aperture, and is drawn in by the dilatation of 

 the muscular investment of the body ; but the contrac- 



