1878. J 



CLASSIFICATION OF THE CERV1D.E. 



895 



Facts (continued). 



(3) The antlers of the Euro- 

 pean Procervulus and of some 

 species of the North-American 

 Cosoryx appear to have been 

 persistent. 



(4) The antlers of Dicroceros 

 and Cosoryx possessed one, or 

 at most two tines. 



(5) The increase in the com- 

 plexity of the antlers of extinct 

 species accompanies their chro- 

 nological sequence in geological 

 time. 



(6) In a conversation which I 

 have lately had with Prof. Marsh, 

 he informed me that some of the 

 specimens of Cosoryx collected 

 by him in North America were 

 tetradactyle. The lateral meta- 

 carpals in these specimens are 

 excessively attenuated in the 

 centre third of their length. In 

 other specimens Prof. Marsh 

 tells me a natural separation had 

 taken place between the proxi- 

 mal and distal ends of the bones. 



(7) The condition of the late- 

 ral metacarpals separates exist- 

 ing Deer into two great groups, 

 the Plesiometacarjri and Tele- 

 metacarpi. 



Hypothesis (continued), 

 remained unantlered ; and spread- 

 from the centre of their geogra- 

 phical area (13), which was pro- 

 bably in the Eastern Palaearctic 

 and Indian regions, they passed 

 westward into Europe, and east- 

 ward into North America. (3) 

 Processes then became developed 

 from the frontals, which gradu- 

 ally elongated and in some in- 

 stances branched. At first these 

 outgrowths from the frontals 

 remained persistently attached ; 

 but eventually the great advan- 

 tage enjoyed by individuals who 

 through necrosis lost, and through 

 an inherited tendency to produce 

 frontal processes renewed their 

 antlers, over individuals who 

 retained antlers broken and 

 rendered useless by frequent 

 combats, caused the natural se- 

 lection of the former in the 

 struggle for existence. (4, 5) 

 These first deciduous antlers 

 were exceedingly simple ; but as 

 time rolled on the advantage of 

 large and complex antlers as a 

 means of offence and defence 

 established an ever-increasing 

 tendency towards complexity in 

 their form. (6) A diminution 

 in the size of the lateral digits of 

 the early forms of Deer accom- 

 panied the increase in the size of 

 their antlers. The centre part 

 of these bones, after attaining an 

 extreme degree of atrophy, at 

 last ceased to ossify. (7, 8) In 

 some species the default in ossi- 

 fication took place nearer the 

 distal than the proximal extre- 

 mity of the bone. In others the 

 converse obtained. The reduc- 

 tion of the rudiments steadily 

 continued, resulting eventually 

 in the disappearance of the 

 shorter rudiment in both forms. 

 Hence the origin of the plesiome- 



