56 THE MAMMALIA. 



man than with us, but has never yet been found opposable. 



This paper is now drawing to a close. My object in writing it 

 has been to draw the attention of those who are not professed 

 palaeontologists, to the profound obscurity in which the laws 

 governing the appearance, duration, and disappearance of species, 

 are still shrouded. Some lowly forms live on through every 

 possible vicissitude. They flourished in the Miocene, and they 

 flourish still. Other low forms disappear with astonishing rapidity, 

 whole orders becoming absolutely extinct. Some highly-specialised 

 forms— high, too, in the scale of intelligence — live on and head 

 the animal kingdom at the present day. Such are the elephants. 

 Others developed rapidly to a very high point of specialisation, 

 only to die out as rapidly. Such forms were Machairodus and 

 JlycenodoN. 



My second object has been the hope that the attention of 

 anthropologists and travellers might be again drawn to the possi- 

 bility of finding surviving semi-human forms, such as we may 

 imagine Miocene man to have been. For palaeontology shows 

 that an animal does not necessarily die out in giving birth to a 

 higher form. The undifferentiated primitive form and the highly- 

 specialised descendant may continue to exist side by side. 



Note. -Since writing this paper, I see in the American Natural- 

 ist for July that Professor Cope, the highest living authority on 

 Mammalian Palaeontology, is of opinion that man was derived 

 directly from a lemuroid form, without the intervention of the 

 anthropoid apes. This he infers, not only from the generalised foot 

 of man, but from lemuroid characters in his superior molar teeth. 

 The nearest approach to the original Eocene type from which the 

 hoofed animals, monkeys, and man are descended, is considered 

 by Professor Cope to be Pheiiacodus Pritneviis. 



I may add that Professor Wallace considers that some skulls 

 found lately in Calfornia were possibly of Miocene age (see 

 Ninetee7ith Cc?itury^ November, 1887. 



