134 THE HOMOLOGIES OF THE 



a weapon that it consists of bone only. What, then, during 

 growth is the structure that in the deer seems to correspond 

 homologically with the horny part of the antelope's or 

 bullock's horn ? During the rapid growth of the antler 

 there is manifestly not sufficient time for the formation of 

 true horny matter, and the skin is then covered with hair 

 only, which I conceive to be the homologue of the horny 

 part of the bullock's or antelope's horn. In some species 

 used to a warm climate this hair is fine, scanty, and soft ; 

 while in others, as the reindeer, which is fitted for a cold 

 climate, the ''velvet," as it is called, is often coarse and 

 shaggy. 



In the rhinoceros the growth of the horn is quite out 

 of proportion to that of the bone, which simply consists of 

 a slight roughening or knobbing of the bones of the face, 

 which support the horns. Near the hollow base of the horn 

 where it grows from the skin organ, the horny matter can 

 be readily split up into hair-like fibres, and in the horn of 

 bullocks and antelopes generally a longitudinal striation of 

 the surface and of the interior can be traced, which seems 

 to mark its close alliance with hair-structure. In some 

 species of antelope this longitudinal striation is especially 

 marked, as in the serows of India and the chamois 

 of Europe. These hair-like fibres are less apparent in the 

 older part of the tip of the horn, but still they can often 

 be traced from end to end, both in the rhinoceros and 

 in the hollow-horned ruminants generally. In many 

 species of the latter, too, we commonly see various ribbed 

 and knobbed patterns produced upon the surface which 

 often serve to distinguish the particular species or genus 

 from others. These rings and elevations of the surface 

 may, I think, represent a periodical increase of activity 

 in their growth somewhat akin, although in a very minor 



