74 R. W. SHUFELDT. 



families of rats, rabbits, squirrels, marmots, and their various 

 allies. So far as existing species are concerned, their common 

 dental formula isolates them completely, while some discovered 

 fossil forms point to their probable kinship with the ungulate 

 series (compare the Mesotherium and the Toxodontia). 



Two other now distinct ordei"s are recognized in the Insec- 

 tivora and the Carnivora, but we find them to be far more 

 closely allied when we come to study the discovered fossil 

 remains of mammals, as above pointed out. 



Especially does this apply to those early and primitive car- 

 nivores, called by Cope the Greodonta. Professor Flower 

 seemed to believe that the "transition from the Insectivores to 

 the Lemurs is not great, and, strange to say, however different 

 they now appear, the early forms of Lemurs are not easily 

 distinguished from the primitive Ungulates". 



Allied to the Insectivora we have another very distinct order 

 of existing mammals. This includes, and includes only, the order 

 Chiroptera. They, as we well know, are all volant mammals, 

 possessing extraordinary modifications of their pectoral limbs, 

 in the development of alar membranes, stretched between the 

 immensely elongated fingers. 



In the last order of all, namely the Primates, we place the 

 various subspecies of men, and all the various family groups 

 containing the Apes, Monkeys, and their allies. 



Through what forms, either extinct or existing, the Honii- 

 nidae and the Simiidae and other simian families are linked 

 with the mammalian orders nearest allied to them is a question 

 not yet definitely settled. 



The secret is still locked up in the crust and caverns of 

 the earth, though the researches of the palaeontologist, the anthro- 

 pologist, and the archaeologist are slowly but surely solving this 

 great, and to man, very important problem. 



Within comparatively recent years a number of fossil or 

 subfossil forms of very primitive types of men have been dis- 



