ORIGIN AND SIGNIFICANCE OF SPINES 



53 



increasing complexity of the antlers during more modern 

 times cannot have improved their usefulness for protection 

 or fighting (figures 42, 43), and probably arose through 

 gradual specialization according to the law of multiplication 

 of effects, acted on by the agency of sexual selection. In 

 some species, as the Reindeer (Rangifer tarandus}, the differ- 

 entiation of the antlers has secondarily produced a useful 

 structure. One of the brow tines in this species has become 

 greatly enlarged and palmated, and serves to assist in remov- 

 ing the snow to uncover food. Evidently this has had some- 

 thino^ to do with the common retention of the antlers in both 



sexes. 



41 



42 



43 



Figure 41. — Antler of Cervidus (?) dicranoceros. Plioccue. 

 Figure 42. — Autler of Cervus pardinensis. Pliocene. 



Figure 43. — Antler of the Fallow Deer (Cervus dama). Reduced. (After 

 Nicholson and Lydekker.) 



Certain types of horns are common to particular regions, 

 especially when the cattle are in a semi-wild state, as in the 

 Western Plains of America. The Texas cattle have long, 

 gently curved horns standing out from the head. Similar 

 forms are prevalent in the cattle of southern Italy and in 

 other warm temperate regions. Further north, the horns 

 become more curved in a direction parallel with the head, 

 and are therefore closer to the skull. The most northerly 

 representative of the hollow-horned ruminants, the Musk-Ox 

 (^Ovibos mo^cAa^ws), has the horns hanging down close to the 

 skull and only curved outward in their distal portions. 



