476 



THE HOESE'S POSITIOX IN THE ANIMAL WORLD 



Ungulate mammals are described by Sir W. Flower as animals which 

 are eminently qualified for a life on land, and in the main for a vegetable 

 diet. Their molar teeth have broad crowns with tuberculated or ridged 

 grinding surfaces, and they have a perfect set of milk teeth, which are 

 changed for permanent ones as the animals advance towards maturity. 

 A very important point in their anatomy is the absence of collar-bones 



deles). Their toes are 





^—1 r—' — 1 r—~^ 



ULUU 1 



covered with horny material, 

 which usually encloses them 

 completely, forming broad 

 blunt nails or hoofs. 



Cuvier, and after him 

 Owen, distinguished two 

 well-marked groups of un- 

 gulates, the fossil remains of 

 which are found throughout 

 the Tertiary period, the 

 Artiodactyla or even-toed, 

 and the PerissodactyJa or 

 odd-toed animals, both still 

 represented by living forms. 

 To realize the significance 

 of these divisions it must 

 be borne in mind that the 

 number of toes in mammals 

 is limited to five on each 

 extremity. Each toe is the 

 end of a series of bones start- 

 ing from a compound joint, 

 the carinis or wrist in the 

 front or upper extremity 

 (arm or fore-leg), and the 

 tarsus or heel in the hind 

 or lower extremity. To the series of bones the name digits is applied 

 to express either fingers or toes, and the term ^^/ia/a^^f/es is used to 

 indicate the separate bones of which the digits are composed. 



The annexed diagram, with the description taken from Professor Sir 

 W. Flower's work, will make the above remarks intelligible. 



So far all is cpite simple; but it happens in nature, and it may also 

 occur by chance, that one or more of the digits may be missing. Still 

 the biologist is expected to decide from those which remain whether the 



Fig. 654. — A, Diagram representing the Bones of the Right Fore- 

 foot of an Odd-toed or Perissodactyle Animal. B, Diagram of the 

 Bones of the Foot of an Even-toed Artiodactyle Animal, c, The 

 Carpus or Wrist (liuee of quadruped), consisting of two rows of 

 bones 



The upper row consists of c, cuneiform ; I, huiar ; and s, scaphoid ; 

 the lower row ii, unciform ; m, magnum ; and /rf, trapezoid ; with 

 the trapezium, tm, behind the cuneiform. The shaded parts of the 

 bones in A are those that are now present in the horse ; in B, those 

 that are present in the ox. In five-toed mammals the digits are 

 numbered one to five, beginning from the inner side of the limb. 

 Digit No. I in the upper or fore extremity is the thumb {/mllej:), 

 and in the hind or lower extremity the great toe [liallex) ; the other 

 digits are distinguished by the figures II, III, IV, and V. 



