626 



ANATOMY OF VERTEBRATES. 



493 



is a little in advance of these angles (vol. ii. fig. 320) : in the 

 Buffaloes and Bubaline Antelopes the horn -cores rise by broad 

 and extended bases, meeting at the mid-line (Buhalus Caffer, 

 B. moschatus, B. Gnu) : in Antelopes the origin of the horns are 

 more in advance. The shape, size, length and direction of the 

 horns vary extremely in the hollow-horned Ruminants : in many 

 they are transversely ridged or annulate ; but several rings may 

 be formed in one year : a periodical activity of growth is notice- 

 able in most, as in the Ram and Goat, toward the period of the 

 rut. Horns are usually present in both sexes ; but in some genera 

 of Antelopes (Tragelaphus, Cervicapra, Cephalophus, e.g.) only in 

 the male. In Antilocapra the rudimental horns in the female 

 are sometimes conspicuous, but are small, short, and simple, as in 

 the yearling-buck. 



The Prong-buck acquires its full-sized horns by progressive 

 growth of the persistent core and by annual shedding and renewal 

 of the extra-vascular sheath. The latter phenomena have been 



witnessed and recorded by two 

 trustworthy observers. Mr. 

 Bartlett noticed their fall in a 

 young male at the Zoological 

 Gardens, November 7th, 1865: 

 the shed sheath was 8 in. long, 

 and showed an obtuse begin- 

 ning of the lower prong of the 

 fork, fig. 493, A, c. The 

 dermo-perioste of the core does 

 not lose its vascularity : the 

 shedding of the agglutinated 

 fibres of the sheath, like that 

 of the ordinary hair, is due to the obliteration of the matrices of 

 these fibres and their extrusion from the dermo-perioste ; which, 

 in the meanwhile, has begun to develope a new coat of fibres, ib. b. 

 These, on the shedding of the old mass, appear as an abundant 

 covering of long, straight, silky and light-coloured hairs, ib. d, 

 the growth of which mechanically uplifts and pushes off the old 

 sheath. The new sheath, 4 inches long when so exposed, grew 

 to 6 inches in the course of three weeks, at which time the fibres 

 had begun to felt or agglutinate into a compact horn at the sum- 

 mit, fig. 493, B, e} 



Dr. Canfield observed in a young yearling male Prong-buck, 

 which he had captive, at Monterey, California, the growth of the 



1 ccxxrv". p. 719. 



Sheddinpr and formation of horny sheath of horn, 

 Antilocapra Americana, ccxxiv". 



