Artiodactyla — Hippopotami, etc. 



41 



placed together, they are bilaterally symmetrical ; the axis or Hippopota- 

 median line of the foot passing down between them, whilst in mus - 

 the Perissodactyles, the axis or median line passes down the 

 centre of the third digit. 



In all the modern Ruminants (with the single exception of 

 Hyomoschtis), the metacarpals and metatarsals are ankylosed 

 together so as to form one bone (the " cannon-bone "), whereas, 

 in the Xon-ruminants, the bones of the feet remain separate, and 



iv m 



Fig. 49. — Examples of modifications of the bones in the Artiodactyle Fore-foot (after 



Flower;. 



A, Pig, \ nat. size. B, Deer, \ nat. size. C, Camel, -£- nat. size. 



B=radius; U=ulna; c = cuneiform : £=lunar; s=scaphoid; «=unciform; , ( i = magnum; 



td= trapezoid. 



The Eoman numerals indicate the corresponding toes, or digits, present in each foot. 



[Beproduced, by permission, from Sir William Flower's Introduction to the " Osteology of 



the Mammalia," 3rd edition, 1885, p. 297.] 



are seldom ankylosed together. The existing Artiodactyla are 

 readily divided into two very distinct groups : firstly, the rTon- 

 ruminants, which have been named the Bu:n t odonta,* embracing 

 the hippopotamus and the pigs ; and secondly, the Ruminants — 

 animals which chew the cud — these are named SELENODO]s T TA,t 



* From &ovi>6q, hilly, and dcovg, a tooth, in allusion to the irregular hilly 

 or marnmillated structure of the molar teeth in the pig and hippopotamus. 



f From fftXtfvig, crescent, and boovq, a tooth, in reference to the crescent- 

 shaped structure of the dentinal folds in the molar teeth of deer, antelopes, 

 oxen, &c. 



