164 ACQUIRED CHARACTERS sec. 



by Lamarck as evidence of the effect of use in the formation 

 of new characters, in order to employ it in my own argument. 



Lamarck says of the Euminantia, in reference to the 

 origin of their horns : " In their ebullitions of wrath, which 

 principally occur in the males, their emotions by their 

 intensity direct the fluids more strongly to this part of the 

 head (the forehead), and therefore there takes place in the 

 one case a secretion of horny substance, in the other a 

 formation of bone -tissue mixed with horn -tissue, by which 

 solid processes are formed ; hence the horns of the ox tribe 

 and stagj tribe." 



Shortly before this he mentions that the ruminants fight 

 together by pushing with the forehead, but it does not occur 

 to him to seek in this fact the stimulus which causes the 

 formation of horns. In my opinion the first beginnings of 

 the formation of frontal processes in the Cavicornia, and of 

 the antlers in the Cervidse, are to be attributed to this 

 stimulus. By the inheritance of a simple swelling on each 

 side of the frontal bone, by the continued inheritance and 

 increase of this swelling in consequence of constantly re- 

 peated stimulation, the frontal processes were produced in 

 Cavicornia, and also the antlers among the Cervidae. The 

 latter, having a special form in each species, and regularly 

 advancing in development and perfection each year up to a 

 certain limit, afford one of the best examples in support of 

 my conception of organic growth in the animal kingdom. 

 For although selection plays some part in this development, 

 it cannot possibly have had in view from the first the form 

 peculiar to each species, and have brought it into existence 

 unaided by other causes. That the ultimate cause of the 

 development lies rather in regular processes of growth is 

 shown by a fact concerning the antler of the roe-deer, which 

 is of particular importance in relation to my whole view. 



The antler of the roe-deer is known to be distinguished. 



