ZOOLOGICAL POSITION AND STRUCTURE i 5 
living mammals ; but a little consideration will 
show that the ox, together with all the other members 
of the family Bovidce, and likewise the giraffe and 
deer tribes {Giraffidce and Cervidce), is really entitled 
to this position. For whereas in the former, as 
shown above, the specialisation is restricted to the 
middle toe and the corresponding metacarpal and 
metatarsal bones, without any essential modification 
of form or fusion of elements, in the latter there has 
been profound alteration in the shape of the two 
enlarged and modified toes, and likewise a complete 
amalgamation, in the respective limbs, of the corre- 
sponding metacarpal and metatarsal elements. 
Compared with their extinct polydactyle fore- 
runners, the ox and the horse have, on their own 
respective lines, attained practical perfection in regard 
to the structure of the bones of the foot ; and whereas 
it would be perfectly easy to suggest modifications in 
the structure of the skeleton of the feet of polydactyle 
animals, such as the rhinoceros, the hippopotamus, or 
the dog, no such modification could be suggested in 
the skeletal structure of those of the ox and the 
horse, save the elimination in the former of the small 
second and fifth toes — which, as mentioned above, 
has actually been accomplished in the case of certain 
antelopes and the giraffe and okapi — and in the 
latter of the so-called splint-bones, or remnants of 
the second and fourth metacarpals and metatarsals. 
In foot-structure the giraffe, the prongbuck, and the 
pala antelope are, therefore, not only more specialised 
than the ox, but even than the horse. The retention 
of the lateral toes in the ox is probably due to the 
fact that this animal lives on softer ground than the 
giraffe. 
