HIPPOPOTAMUSES, PIGS, AND DEER 289 



somewhat soft sheath of branching horn. This horny sheath in 

 the prongbuck is shed annually and grows up again. In the 

 third family about to be described (the Deer) there is, first of 

 all, a permanent bony pedicle, or core, developed from the skull. 

 (In the muntjacs, a somewhat primitive and ancient type of deer, 

 these pedicles are several inches long, and often more important 

 in length than the little antler which grows from them.) From 

 the end of this bony projection, or pedicle, the deer start another 

 and independent growth of bone, which in the earliest or least de- 

 veloped types of deer is a mere prong or a simple fork. But in all 

 the more extravagantly developed types this additional detachable 

 growth of bone at the end of the permanent pedicle is often of 

 enormous size and weight. Whilst this bony antler is develop- 

 ing during several months, and until its extreme growth has been 

 reached, it is covered outwardly with blood-vessels, skin, and 

 hair, so that in that condition it resembles the " horns " of the 

 giraffe ; but when the growth of the antler is complete, the 

 blood-vessels dry up, nourishment ceases to reach the skin and 

 hair, and thus the " velvet " is soon rubbed off by the stag, 

 leaving the naked and dry bone. This lessening of the nutrition 

 continues long after the velvet has disappeared ; and finally, about 

 ten months from the time at which the additional growth of bone 

 has started,^ the complete antler, as far as its connection with its 

 parent pedicle, is easily detached and falls off. 



In the last family of this group, the Bovid^^ or Hollow- 

 horned Ruminants (Cattle, Tragelaphs, Capricorns, Sheep, and 

 Antelopes), the original bony projection from the skull is con- 

 tinuous with the skull bones and of a permanent nature, growing 

 sometimes to extraordinary lengths. It is never known to branch, 

 as in the aberrant giraffes. As this bone grows up from the skull 

 it is covered by a sheath of horn (no doubt a modification of an 

 original hairy covering), and this horn cap ends in a sharp point, 

 and often considerably exceeds in length the bony core. It has 



^ This period refers to deer — the vast majority — which only renew their 

 antlers once a year. It is, of course, proportionately shorter where (as in 

 Pere David's deer) the antlers are tzvice shed in the twelve months. 



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