In the domestic Horse they vary in shape. In the fore-legs 

 they are either pointed up and down, or, as in Fig. 84 (a\ pear- 

 shaped ; and in the hind-legs they are often like slits in the skin. 

 I have not seen a second case of a Horse without them on the 

 hind-legs, but perhaps a more extensive search might discover 

 some others. 



Now, are there any other animals with similar callosities on 

 their legs ? Yes ; Professor Flower has mentioned the Meminna 

 and Tragulus^- two Deer-like or Swine-like ruminants. In the 

 Natural History Museum the Huanaco (Lama huanacus) has 

 similar callosities on both the inner and outer aspects of the hind- 

 leg below the hock. The Llama (Lama glamd] has them also on 

 both sides of the hind-legs. The Alpaca (Lama pacos] in some 

 cases seems to have them only on the inner aspect of the hind-legs. 2 



Fig. 84 (b) gives an outline of the hind-leg of the Alpaca, 

 showing the callosity ; and Fig. 86 gives a full picture of a living 

 Llama, with the callosities, as slits, on both aspects of the hind-legs. 



It is interesting to note that in the Vicugna (Fig. 84 (V)), another 

 Cameloid animal of South America, instead of a callosity, there is, 

 in this case at. all events, in the same region, a distinct tuft of 

 elongated dark hair on a light ground. 



Then again in the Natural History Museum there are various 

 other ruminants which have, as I think, very significant tufts of 

 hair on the inner aspects of their hind-legs which are of a different 

 colour from the general ground colour. 



The Elk, the Virginian Deer, and the Peruvian Roebuck all 

 American ruminants have these suspicious tufts of hair on their 



1 The callosity on the metatarsus of Tragulus may mean something else (see end 

 of Part vi.). 



2 At Tring, the Vicugna has callosities, like slits, on both aspects of hind-legs, below 

 the hock ; and in the Zoological Gardens both the Huanaco and the Llama have 

 callosities in the corresponding places. 



