THE EDENTATES 



(EDENTATA). 



Placental mammals with incomplete dentition and rootless teeth without enamel. 



transformed into sickle-shaped claws. 



The free digits carry hoofs 



It is difficult to find a suitable name and 

 satisfactory distinguishing characters for this 

 order, which is manifestly made up of diverse 

 elements. Linnaeus designated them Bruta, 

 embracing under this term, however, also the 

 rhinoceroses and other animals without in- 

 cisors. The name edentate, invented by 

 Cuvier and now in general use, does not 

 correspond at all to the actual facts. There 

 are indeed in this group certain animals, such 

 as the ant-bear or tamanoir, in which the 

 teeth are altogether absent, but, on the other 

 hand, there are other animals belonging to this 

 order — for example, the giant armadillo — hav- 

 ing more teeth than any terrestrial mammal 

 of any other order. The incisors are almost 

 always wanting, but we know one species, 

 the six-banded arm.adillo, in which the first 

 pair of teeth in the upper jaw, though exactly 

 like the cheek-teeth in form and structure, 

 are set in the premaxillary bone, and must 

 accordingly be regarded as incisors. As a 

 rule there are no canines, but we find in the 

 unau, a sloth, beautiful strong canines both 

 above and below. These are pointed and 

 sharp, and thus considerably different from 

 the ordinary cheek-teeth. It is true that 

 these teeth fit into one another in a different 

 manner from the canines of other mammals, 

 so that when the mouth is shut the upper 



comes in front of the lower, yet this circum- 

 stance should not lead to any difference in 

 the naming of the teeth, any more than the 

 fact of a tooth placed in the premaxillary 

 bone agreeing in form and structure with the 

 cheek-teeth would deprive such tooth of the 

 character of an incisor. 



But even apart from these details we must 

 acknowledge that all these teeth are con- 

 structed on a quite peculiar plan. They 

 show no trace of enamel, and consist solely 

 of dentine overlaid by a layer of cement, 

 which sometimes rises from the part set in 

 the socket a considerable way up towards 

 the crown with considerable thickness. The 

 teeth never have roots; in one genus, Oryc- 

 teropus, they even consist of a number of 

 small prisms united by cement, each of the 

 prisms having a vertical canal filled with 

 pulp. This kind of dentition calls to mind 

 that of certain fishes. 



The claws also deserve special attention. 

 In some genera, as in the sloths, they are 

 enormous sickle-shaped sharp implements, 

 flattened at the sides; in others, again, they 

 are broad and well adapted for burrowing in 

 the earth. Their form, however, is a matter 

 of no moment. As regards their structure 

 they are in every case hoofs, that is, they do 

 not merely cover the last phalanx of the toes, 



