308 



UNGULATA 



tions of these parts are most variously combined in different 

 members of the group. It appears, however, extremely probable 

 that they soon branched into two main types, represented in the 

 present day by the Cervidce and the Bovidce, otherwise the 

 antlered and horned Euminants. Intermediate smaller branches 

 produced the existing Musk-Deer and Giraffe, as well as the extinct 

 Helladotherium inclining to the first-named group, and the extinct 

 Sivatherium, Erahmatherium, Hydaspitherium, and others more allied 

 to the latter, although upon the true relationship of these forms 

 there is a difference of opinion. 



The earliest forms of true Pecora, as Palceomeryx, generally had 

 no frontal appendages, and some few forms continue to the present 

 day in a similar case. In the very large majority, however, either 



in both sexes or in the male 

 only, a pair or occasionally two 

 pairs (Tetraceros and the extinct 

 Sivatheriwm) of processes are de- 

 veloped from the frontal bones 

 as weapons of offence and de- 

 fence, these being almost always 

 formed on one or other of two 

 types. 



1. " Antlers " are outgrowths 

 of true bone, covered during 



their growth with vascular, 

 sensitive integument coated with 

 short hair. When the growth 

 of the antler is complete, the 

 supply of blood to it ceases, the 

 skin dies and peels off, leaving 

 the bone bare and insensible, 

 and after a time, by a process 

 of absorption near the base, it 

 becomes detached from the skull 



FIG. 119. A shed right antler of the Red Deer an d IS " shed " (Fig. 119). A 

 (Cervus elaphus), found in an Irish lake, a, Brow more Or less elongated portion 



line.' 6 (AfteVo n Jeny reS ""* ' *' "^ ^ ^ OT " ^^^ " alWayS remainS On 



the skull, from the summit of 



which a new antler is developed. In the greater number of exist- 

 ing species of Deer this process is repeated with great regularity at 

 the same period of each year. The antler may be simple, straight, 

 subcylindrical, tapering and pointed, but more often it sends off 

 one or more branches called "tines "or "snags" (Fig. 119). In 

 this case the main stem is termed the "beam." Commonly all the 

 branches of the antler are cylindrical and gradually tapering. 

 Sometimes they are more or less expanded and flattened, the 



