Glass 6. Mammalia. Order 11. Brnta. 



527 



tivorous. xuther small or of medium size ; some forms can roll themselves up : 

 South America and the southern parts of North America. Allied to them are 

 the extinct Glyptodons, in which all the dorsal plates were immovably 

 united to form a large, thick, arched coat of mail ; large portions of the vertebral 

 column were also fused ; they were extremely clumsy animals and of consider- 

 able size. Quatemaiy of South America. 



5. The Cape Ant-eaters or Aardvarks (Orycieropus) are animals 

 of fair size ; sparsely haired ; with long snout and tongue ; small mouth ; large 

 pinnae ; powerful tail ; strong, but not very long claws ; possessing teeth : Africa. 



6. Pangolins or Scaly Anteaters (Manis) are specially 

 characterised by having the dorsal region of the body covered with large, 

 very homy, imbricating scales, between which a few hairs appear. The head is 

 long ; pinnse are absent ; the mouth is small and edentulous ; the tongue long ; the 

 tail is powerful ; claws long and falciform. Insectivorous and representing the 

 Ant-eaters (which they resemble in many respects) in the tropical regions of the 

 Old World. 



Order 12. Rodentia {Jtodents). 



The Rodents are primarily characterised by the peculiar 

 dentition. Canines are absent; there is only a single 

 incisor in each side of the lower javr, situated anteriorly and 

 close to its fellow ; there is usually also only one in the premaxilla^ 

 placed as in the lower jaw ; the incisors are long and grow from 

 persistent pulps, they are almost quadrangular prisms and are 

 curved; the enamel only 

 covers the front and the 

 lateral edges^ its surface is 

 sometimes reddish brown; 

 the free end of the tooth 

 is cut away obliquely like 

 a chisel. The upper incisors 

 have a greater curvature 

 than have the lower one.s, 

 in both cases the fiortion 

 within the jaw extends far 

 back, m the lower usually 

 even to the most posterior 

 extremity below all the 

 molars. In the Leporidte 

 there is a smaller incisor 

 behind the large one in the 

 upper jaw ; it may also be 

 noticed that here the lower 

 incisor only extends back 

 as far as the front end of 

 the molar series (Fig. 422 A). There is always a large diastema 

 between the incisors ai;d molars ; the molars exhibit a great 



Fig. 422. Eight ramus of the mandible, 4 of a 

 Babbit, B of an Agouti, from the inner side. Sockets 

 of the incisors removed for their whole length to 

 show the different lengths of the tooth. B gives the 

 usual rodent condition. — Orig. 



