220 WHALES. 



cavities have valves, near their upper extremities, 

 which open only from below, and thus retain any water 

 that may be forced up by the circular construction of 

 the canal that leads from the larynx. Above those 

 valves there are two elastic sacs, capable of containing 

 a considerable quantity of water, and also of contracting 

 with great force ; and the structure of the whale is such 

 that the water, which must, in some portion at least, 

 always get as far as the gullet, can be sent to those sacs 

 without interrupting the respiration of the animal. 

 Thus the whale is enabled to swim and feed open- 

 mouthed, without the water either entering the stomach, 

 or disturbing its breathing; a contrivance essential to 

 its mode of life. The water appears to go to those 

 receptacles always when the animal swims with its 

 mouth below the surface ; but only in a small quantity ; 

 and while it does so, it prevents the accumulation of 

 mucus in the breathing apparatus. But there is no 

 waste of power ; the discharge of the water is not so 

 constant as its reception. It is a voluntary operation, 

 performed at intervals, and with much force. The 

 compression of the sacs projects the water, through 

 the blow-holes, to the height of nearly fifty feet, and 

 with much noise, both by the ascent of the water, and 

 by its fall. This operation is called spouting, and it is 

 one of the means by which whales are found in foggy 

 weather, as it is audible at a considerable distance. 



Whales are now usually divided into four orders : 

 1. Toothless whales, (edentatce,) or those that have 

 not teeth in either jaw ; 2. Upper-toothed whales, 

 (pr<zdentat<z,) or those that have teeth only in the 

 fore-part of the upper jaw ; 3. Lower-toothed whales* 



