1902.] OF HORNS AND ANTLERS. 209 



integument of the Giraffe is only hairy, that of the Prongbuck is 

 hairy and horny, that of the Bovidee only horny. Having 

 satisfied himself about the apophysial nature of the antlers in 

 opposition to the epiphysial condition of the bony core of the 

 Giraffe and Bovidse, he naturally feels justified about the com- 

 plete removal of the Giraffe from the Cei-vidse and the funda- 

 mental difference between bovine and cei-vine ruminants. 



These conclusions are not satisfactory. First, it is not likely 

 that several fundamentally different kinds of armaments should 

 have been developed within such a cu^cumscribed and specialized 

 group as the higher Ruminants or Pecora. It is of greater 

 scientific value if we can trace all these armaments not only to 

 the same beginning, but bring them all into one evolutionary 

 line, so that these organs afford a clue to the phyletic develop- 

 ment of the various groups of Ruminants. The ultimate cause of 

 these armaments must have been the same, namely butting with 

 the head, causing irritation, which in turn leads to hypertrophy 

 of the cranial bones, together with the covering periost, cutis, 

 and epidermis \ 



Secondly, the origin of the os cornu, sometimes with a separate 

 centre of ossification, has to be accounted for, since it is quite 

 impermissible to assume that it was a preformed bone in the 

 skin, which has later become fused onto the skull. Nor is there 

 a single instance in mammalian pathology of loose ossification in 

 the cutis due to repeated pressure or irritation, conditions which, 

 on the contrary and invariably, lead to exostosis of the underlying 

 already existing bone. 



Thirdly, there is the pal?eontological evidence, not very plen- 

 tiful, but one fossil in hand is worth more as a proof of phyletic 

 speculation than ever so many ontogenetic observations. Curiously 

 enough, few palaeontologists, whilst thi'owing much light upon 

 the evolution of the cervine antlers, have tried to take a bi-oad 

 view of the phyletic side of the whole question, and the com- 

 parative anatomists have, as usual, left the fossils severely alone. 



Lastly, there is the Girafie and its relation, the Okapi, the 

 former with multiple, early appearing protuberances in both 

 sexes, the other apparently with none. 



The question at issue requires a renewed investigation of the 

 development of the cervine and bovine araiaments and a sifting 

 of the palseontological evidence. 



I. Development of the Cervine Antlers. 



The first growth of a buck's antler in his first year is aheady a 

 compound structure. It begins with a bulged out elevation or knob 



1 The general considerations and conditions have been well described and argued 

 out by J. J. Cunningham, ' Sexual Dimorphism,' pp. 73-104. The evolution of 

 horns and antlers, studied with due regard to the interesting physiological features, 

 is one of the clearest demonstrations of the acquisition and inheritance of new 

 organs, whilst any attempt to account for them (not their shape !) by variation and 

 selection alone would be ridiculous. 



