4 THE HORSE FAMILY. 



_, , , , Facing: the visitor as he enters the middle of the 



Skeleton of .\ „ , . . w i i f 



north hall are shown m a single case the skeletons 

 Man & Horse. ^^ ^ -^^^ ^^^ ^^ ^ ^^^.^^ (N.H. 1), arranged for 



comparison with each other, and also to show the position of the 

 bones of both in relation to the external surface. In the case of 

 the Horse, the skin of the animal from which the skeleton was 

 prepared was mounted, and, when dry, divided in the middle line^ 

 and one half, lined with velvet, placed behind the skeleton. In 

 the Man the external surface is shown by a papier-mache model, 

 similarly lined and placed in a corresponding position. The 

 principal bones of both skeletons have their names attached, 

 so that study of this group, besides affording a lesson in com- 

 parative anatomy, may be of practical utility to artists. The 

 meanings of the terms pastern, fetlock^ etc. are also explained in 

 this specimen. 



Evolution Specimens illustrative of the evolution of the Horse are 



of the displayed on the north side of the table-case near the 



Horse. middle of the north hail ; that is to say in the same 



case which contains, on the south side, the series illustrating the 



dentition of the Horse. 



The evolution of the Horse (and its allies) is better known 

 than that of any other group of Mammals. In passing from 

 the Horse to its earlier ancestors, a gradual decrease in bodily 

 size (fig. 1), accompanied by a shortening of the lower segments 

 of the limb, especially of the bones of the foot, is very noticeable ; 

 at the same time there is an increase in the number of the toes, 

 while the height of the crowns of the cheek-teeth is lowered, and 

 their structure becomes simpler. 



In the Horse, in common with the other members of the genus 

 Equus, the skull (fig. 13) has the socket of the eye completely 

 surrounded by bone, there is no distinct depression immediately in 

 front of the same, the canine and incisor teeth are separated by a 

 lon^ gap from those of the cheek-series, and the crowns of the 

 latter are very tall and continue to grow till late in life, while their 

 grinding-surfaces are much complicated, owing to the fiUing-up of 

 all the cavities with the substance known as cement. Each limb 

 terminates in a single hoof, upon which alone the animal walks ; 



