LECT. IV.] ISOLATION OF THE EDENTATA. 



uncommon in the highest mammal we are familiar 

 with. 



The evolution of protective characters is seen in this 

 group, I think, better than in any other. 



The Sloth is not only well wrapped up so as to be 

 " warm o' nights ;" he is stained of a greenish colour, so 

 as to be more like the mosses and lichens that grow on 

 the patriarchal trees of the primaeval forest than any 

 proper living creature. Now this greenish tint in his 

 coarse, spongy hair, as Mr Sorby has shown, is due to 

 the growth of an alga in its interstices. Here, again, 

 what would be loathsome in us, is made by nature to be 

 a most wholesome and safe thing for this, the slowest of 

 all the Mammalians. Nevertheless, this overdoing of 

 protection becomes a real danger to these beasts ; they 

 take less care of themselves, and have less and less 

 power to escape danger. 



On the other hand, the most naked and defenceless 

 of all the tribes of the earth has become the lord and 

 governor of all the tribes ; in his case, the protoplasm 

 which has been saved from the skin has gone to the 

 service of the brain. 



Coming to particulars as to the structure of the 

 Edentata, I may remark that the scapula has a very 

 large coracoidal tract, as compared with that of the 

 higher mammals ; this is seen especially in the Sloth 

 and the Ant-eater. The Pangolin, I find, has at times, 

 eight cervical vertebrae ; Sloths may have as many as 



