3i6 PRIMARY FACTORS OF ORGANIC EVOLUTION'. 



must have been protected by skin (I do not observe 

 these grooves on the beam of C. teres). The retention 

 of the broken extremity of an antler, so as to be re- 

 united, as described (Fig. 87, C), could not have been 

 accomplished without an integument. The presence 



of the burrs cannot be 

 accounted for on any 

 other supposition, as 

 there are no foramina 

 to give exit to nutrient 

 vessels at the point 

 where they exist ; the 

 irregularity of those 

 positions also forbids 

 the latter idea, and 

 adds to the probability 

 that the arteries which 

 furnished the deposit of 

 phosphate of lime were 

 contained in a super- 

 ficial dermal coating. 

 The supposition is also 

 strengthened by the fact 

 that the only existing 



Fig. 87.-W, B,Cosory.r necatus Leidy; j-^j^inantS (the giraffcs) 



A, without, S, with, burr on antler; C, D, \ o / 



Cosory-x: raviosus Cope; C, antler broken with permanent homS 



and reunited; /?, beam with burr , one- ^Jtl^Q^jj ^-^ sheaths 



half natural size;- original; from Report ■' 



u. s. Gov. Geoi. Expi. looth Mer., G. M- havc them covcred with 

 ^'^""'"'"- hairy skin. 



" It appears that in the antlers of the Cosoryx the 

 deposit of a burr was immediately associated with the 

 death of the portion of the horn beyond it, so that it 

 disintegrated and disappeared. This was not the case 

 with the beam in the specimens observed. Neverthe- 



