362 PICTURESQUE SKETCHES 



with peculiar habits. The long broad bone, descend- 

 ing by the side of the cheek, is one of those points 

 in which the resemblance to the sloth is carried out 

 very accurately; and this is not less interesting, al- 

 though we are at present ignorant of its exact mean- 

 ing. It is characteristic of the whole group of Eden- 

 tata. 



The teeth of the megathere are large in proportion 

 to their thickness, and are gently curved. Their 

 grinding surface is simple and well adapted to the 

 comminution of leaves and twigs. They are all of 

 them molars (grinding teeth), and there are four on 

 each side of each jaw. They consist of regular four- 

 sided prisms, the outer coating being of bony matter, 

 enclosing a thin inner coating of enamel, and a central 

 mass of ivory ; while the opposing teeth are so placed 

 in the jaw that the enamel of each cuts into the softer 

 bone and into the central ivory of the corresponding, 

 one, so that a grinding surface is constantly and evenly 

 preserved, and two wedge-shaped cutting edges work 

 into one another, and keep one another sharp. 



These teeth were renewed from the root through- 

 out the entire life of the animal, and were gradually 

 pushed forwards as they were needed. They were 

 set very deep in the jaw. It is worthy of notice, 

 that many of these modifications, the narrow palate 

 for instance, the position of the teeth closely set in the 

 jaw, their great length, and the corresponding depth 

 of the jaw, all exhibit a certain amount of resem- 

 blance to the structure of corresponding parts of the 

 elephant, although the fundamental structure of the 

 teeth, and the general form of the skull, is at present 

 exclusively restricted to the sloth family. 



