HORNS OF MAMMALIA. 627 



first pair of horns commencing in July (1855), and attaining the 

 length of -fths of an inch and the form of a mammillary knob : 



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the sheath was shed, early in December, leaving the core ^ an 

 inch long, and covered by fine silky hairs : in a week the agglu- 

 tination of the summit into compact horn commenced. In Oc- 

 tober 1857, the animal beino; two years and a half old, the horns 



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were 9 inches long, and the anterior prong was indicated by a 

 protuberance, as in fig. 493, A, the agglutinate tip of which soon 

 became confluent with that of the main stem. The phenomena 

 noted between 1855 and 1857 indicated an annual shedding of 

 the horn-core. 1 It is probable that such takes place, also, in 

 the fully-formed horn and, in the month of November, as a 

 rule. 2 



The Giraffe has a pair of small, short, cylindroid unbranched 

 horns which consist of bone covered by hairy skin terminated by 



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a tuft of coarser hair. The bones are not processes of the skull 

 but are joined, like epiphyses, by * synchondrosis ' to both frontal 

 and parietal bones, the base crossing the coronal suture. They 

 are present in both sexes (vol. ii. p. 476, fig. 325) ; and the young 

 is born with such horns, being the sole horned mammal that 

 enters the world with these weapons. 3 



In Deer (Cervidce) the horns consist wholly of bone which 

 grows from the frontal, the periosteum and finely haired integu- 

 ment, called ' velvet,' co-extending therewith during the period 

 of growth ; at the end of which the formative envelope loses its 

 vascularity, dries and is stript off, leaving the bone a hard in- 

 sensible weapon. After some months' use, as such, the horns or 

 more properly ' antlers,' having lost all vascular connection with 

 the skull, and standing in relation thereto as dead appendages, 

 are undermined by the absorbent process and shed ; whereupon 

 the growth of a succeeding pair commences. The shedding of 



1 ccxxv". p. 108. 



2 Thus Dr. Canfield observes : ' In the mouth of December and January I have 

 never killed a buck with large horns ; and at that, time of the year all the bucks 

 appear to be young ones, because their horns are so small, whereas in the spring and 

 summer mouths almost all the bucks appear to be old ones, for their horns are then 

 large and noticeable.' He also remarks : ' In the summer months the line of demar- 

 cation is very apparent and abrupt between the horn and the skin from which it grows, 

 but that in winter there is no demarcation, the horn being very soft at its base, pass- 

 ing insensibly into cuticular tissues, and the horny substance being covered thinly 

 with hair.' Ib. p. 108. 



3 ccxxvi". p. 25. A broad obtuse eminence formed by thickening of contiguous 

 parts of the two front als at the part of the frontal suture, the base of which eminence 

 is often irregularly excavated or undermined by vessels, has been mistaken for a third 

 horn, articulated to the frontals. See xcvii'. p. 219 ; and section through this part, 

 vol. ii. fig. 326. 



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