MOUTH OF THE WHALEBONE WHALE. 



781 



Ornithorhynchus, the Echidna, the Sloths, the Elephant, the Seals, and 

 the Orang-Outang, this round ligament is deficient. The arrangement 

 of the other articulations will be at once apparent on reference to the 

 figures of the different skeletons already given. 



(2250.) Turning to the digestive system of Mammiferous animals, 

 their teeth first invite our attention. We have already, when describing 

 the osseous framework of these elevated beings, exposed their general 

 arrangement in the jaws of the different orders ; but it still remains for 

 us to explain the varieties of their structure and the mode of their 

 formation. 



(2251.) The most remarkable form of teeth, one indeed that is 

 unique, is met with in the Whalebone Whale (Bal<ma mysticetus). The 



Fig. 396. 



Mouth of the Whalebone Whale. 



teeth in this Cetacean, indeed, are not instruments of mastication, but 

 form a very curious apparatus, adapted to strain the waves of the sea as 

 through a sieve, and thus obtain from the ocean a sufficiency of food for 

 the sustenance of its monstrous body. 



(2252.) The whalebone (as it is improperly called) is attached to the 

 gums of the upper jaw, being arranged in thin flat plates of some 

 breadth, and varying in length according to the size of the Whale *. 

 These plates are placed in several rows, similar to teeth in other animals ; 

 they stand parallel to each other, having one edge directed towards the 



* J. Hunter, on the Structure and (Economy of Whales (Phil. Trans. 1787). 



