THE CERVID.E, OR DEER. 167 



dually overcome the difficulties presented by the 

 desert. 



Zoologists have always classed the Musk Deer 

 and the Dwarf Musk Deer (Tragulidce) with the true 

 stags, although they are hornless animals. In 

 doing this they have allowed themselves to be led 

 by the general impression that the possession of 

 antlers is not determinative of the relationship ; 

 this had already been affirmed by Alphonse Milne- 

 Edwards in 1864, and has been proved by their 

 connection to the fossil forms that have now been 

 brought to light. From these annexed groups the 

 Hycemoschus aquaticus, which lives on the west 

 coast of Africa, is of great importance as the con- 

 necting link between the present and the remote 

 past. Our Figure 25, A, gives the left fore-foot of 

 this animal. Hycemoschus is also a decided two- 

 hoofed animal, although the two middle metacarpals 

 (in, iv) are entirely separate, and although the 

 two outer metacarpals (n, v) are perfectly com- 

 plete and the two lateral toes are developed and 

 connected. Hycemoschus thus proves itself an 

 adaptive form, inasmuch as the two toes that are 

 no longer of use have ceded their right to the 

 tarsals, to the principal toes, and thus increased the 

 strength of the latter. The skeleton of the fore- 



