232 STUDIES IN THE EVOLUTION OF ANIMALS 



Stable-men call them corns. Professor Flower calls them 

 warts or callosities, or 'chestnuts,' and 'mallenders,' and 'sallenders,' 

 as some old books designate them. 



He says — ' There the skin is peculiarly modified from its usual 

 structure.' No hair grows on these patches ; ' the papillae of the 

 derm or true skin are much enlarged, and covered with an abundant 

 and thick epidermis, which becomes dry and horny, and some- 

 times (in the Horse) accumulates in considerable quantity on the 

 surface, occasionally even making a horn-like projection.' 



Professor Flower ^ adds — ' The signification and utility of these 

 structures are complete puzzles;' and on p. 173, 'They obviously 

 belong to a numerous class of special modifications of particular 

 parts of the cutaneous surface which occur in very many animals, 

 the use of which is in most cases remarkably obscure. Bare spots, 

 thickened patches or callosities, and tufts of elongated hair, often 

 associated with groups of peculiar glands, are very common on 

 various parts of the body, but especially the limbs, of many 

 ungulates, and to this category the "chestnuts'" of the Horse 

 undoubtedly belong.' 



Then, in a note to the same page, he says — ' Dr. J. E. Gray 

 divided the pigmy Chevrotains (ruminants allied to Pigs) into two 

 groups — Meminna, ' with a naked prominence on the outer side of 

 metatarsus, rather below the hock,' and Tragulus, ' with hinder 

 edge of the metatarsus naked and callous.' ^ 



Professor Flower concludes this part of his book thus : ' If they 

 (the corns) teach us nothing else, they afford a valuable lesson as 

 to our ignorance, for if we cannot guess at the meaning or use of a 

 structure so conspicuous to observation, and in animals whose 



^ The Horse, p. 172. 



'^ At the end of Part vi. I made a suggestion which may give a different meaning 

 to the callosity of Traguhis. 



