422 ORDERS OF MAMMALIA. 



supporting the weight of the body. The anterior limbs are 

 shorter than the posterior, and have nothing whatever to do 

 with progression. Tlie thumb is opposable, and the hands 

 are prehensile, the fingers being provided with nails. The 

 toes of the hind-limb are also furnished with nails, but the 

 halhiM is not opposable to the other digits, and the feet are 

 therefore useless as organs of prehension. The foot is broad 

 and plantigrade, and the whole sole is applied to the ground 

 in walking. 



The dentition consists of thirty-two teeth, and these form 

 a nearly even and uninterrupted series, without any interval 

 or diastema. The dental formula is — 



.2—2 1—1 2—2 3—3 



i ; c : pm ; m =32. 



2—2 1 — 1 ^ 2 — 2 3—3 



The brain is more largely developed and more al>undantly 

 furnished with large and deep convolutions than is the case 

 with any other Mammal. 



Pala?ontologically, there is little to be said about Man — 

 or rather, so much might be said on this subject that its dis- 

 cussion can only be properly taken up in a special treatise. 

 Man appeared upon the earth, so far as we know for certain, 

 only in the last or Post-Tertiary period of Geology, and his 

 remains, in the form of bones or implements of various kinds, 

 have been detected in various Post-Tertiary accumulations, 

 such as valley-gravels and cave-deposits. The chief facts 

 as to the past existence of man which concern the palseon- 

 tological student may be briefly stated as follows : — 



1. Man unquestionably existed during the later portion of 

 what Sir Charles LyeU has termed the "Post-Pliocene" period. 

 In other words, Man's existence dates back to a time when 

 several remarkable Mannnals, to be afterwards mentioned, 

 had not yet become extinct ; but he does not date back to a 

 time anterior to the present Molluscan fauna. It should be 

 added, however, that there is some evidence — the value of 

 which cannot be at present accurately appraised — which 

 would go to show that man existed in the later portion of 

 the Tertiary period, in the Pliocene, or possibly even in 

 the Miocene, age. If this were established, then Man, as 



