UNGULATA VERA 275 



which the vast majority of modern Ungulates belong the second or 

 distal row has been shifted altogether towards the inner side of the 

 limb (see Fig. 99), so that the magnum is brought considerably 

 into relation with the scaphoid, and is entirely removed from the 

 cuneiform, as in the great majority of existing mammals. 



It will be on the whole more convenient to commence our 

 survey of the members of this suborder with the more specialised 

 group of the Ungulata Vera, in which the Artiodactyla will be 

 taken first. 



UNGULATA VERA. 1 



In the typical Ungulata the feet are never plantigrade, and the 

 functional toes do not exceed four the inner digit being suppressed, 

 at all events in all forms which have existed since the Upper 

 Eocene period. 2 The os magnum of the carpus articulates freely 

 with the scaphoid. The allantois is largely developed, and the 

 placenta, so far as is known, is non-deciduate ; the chorionic villi 

 being either evenly diffused or collected in groups or cotyledons (in 

 Pecora). The testes descend into a scrotum. There is never an os 

 penis. The uterus is bicornuate. The mammae are usually few 

 and inguinal, or may be numerous and abdominal (as in Suina), but 

 are never solely pectoral. The cerebral hemispheres in existing 

 Ungulates are well convoluted. 



The group is now, and has been throughout almost the whole 

 of the Tertiary period, composed of two perfectly distinct sections, 

 differing from each other, not only in the obvious characters of the 

 structure of the limbs, but in so many other parts of their organisa- 

 tion that they must be considered as of the rank at least of 

 suborders. The characters of these divisions, first indicated by 

 Cuvier, were thoroughly established by Owen, by whom the names 

 whereby they are now generally known were proposed. 



Suborder ARTIODACTYLA. 



This is a well-defined group, traceable from the Eocene period, 

 though then apparently by no means so numerous as the Perisso- 

 dactyles. Some of its types, as that represented in the existing 

 Swine, have retained to the present time much of the primitive 

 character of the group ; but others have been gradually becoming 

 more specialised and perfected in structure, and its latest modifica- 

 tion, the Cavicorn Ruminants or Biwidce (Antelopes, Sheep, and 

 Oxen), are now the dominating members of the great Ungulate 

 order, widespread in geographical range, rich in generic and specific 

 variation, and numerous in individuals forming in all these 



1 Also known as Diplarthra. 

 - The pollex is present in the nianus of the extinct Cotylops. 



