8 ETNAK LoNNRERfi, sTUDTES ON HtJMiNANt.S. 



attains the sliape of m T l»eaiii which with retreiichinent of materinl is the most snitable 

 construction. It is then possible that the development of tho ridgc^s causes imeven growth 

 which results in a spiral 1'otation of the ovuan. This is the iiioi'e prolwble as tho horny 

 slieath is thinnest betAveen the two most developed ridges. 



The horns of Sf)r-'p.'<icero.<< may ho vegarded as a further specialisation in the same 

 direction as the type exhibited by Iraqelaphitf:. In Strepsicero.^, too, the coves extend 

 throngh fvilly fonr fiftlis of the entire length of the hovn. But the horny sheaths of 

 this animal are comparativelv stronger, especially through the greater deAelopraent of 

 the ridges \vliich strengthen the horns in such a. manner that they can practically be 

 regarded as spirally twisted T beanis. The strongest ridge is, in this ease, the one whicli 

 is basally sitnated in front, and tliere at the most critical plaee braces the horn in the 

 sagittal plane. Another ridge, althongh not so strong, is found latero-posteriorly, tlius 

 eorrcsponding to the one Avith similar situation in Trafielapliuf. When the horns are 

 fullgrown this ridge becomes quite obsolete in the basal region, at lea-st exteriorlj^, but 

 a, thickening of the horny sheath ean be distinguished Qxen when exteriorly no ridge is 

 visible. The third ridge is not at all prononnced in the kudu. The side of the hornj' 

 sheath which is basally the median one, is provided with transverse ribs on the proximal 

 ])arts of the horn. These ribs are stronger in old aninials. 



The elements of the horny substance are conspicuously longitudinally arranged. The 

 core consists chiefly of con\])act bony tissue, the centre of which is longitudinally traversed 

 by a number of mostly large <^,anals for bloodvessels (conf. fig. 4, Pl. I). In the l)ase of th(! 

 eore (conf. tig. 11, Pl. II) in the same place where the small basal sinus is found in Trnge- 

 lajilnif, there are some comparatively small sinuous vacuities, the largest of which is, how- 

 ever, mostly taken up by a. netAvork of spongious tissue so tine, l)ut with so large rneshes 

 that it might be compared with a cobweb. The whole is surrounded by \ery thick and 

 even basally perfectly eompact walls. In the tip of the eore the interspaces between the 

 canals for the bloodvessels are also oecupied by a spongious tissue Avith rather large 

 meshes. (^ther^vise the core is (piite eompact as has already been remarked. The tip of 

 the core is, unlike that of Traqrlaphu.^, more weakly built, but it is sufticiently protected 

 by the horny sheath Avhich attains a considerable thickness. — From this description may 

 be concluded that the horns of Strepfieeros are, through the compactness of the core and 

 the thickness of the sheath, very strongly built. Their spiral shape adds to their elasticity 

 so that they, if need be, might be more benT without risk of breakage than if they had 

 been straight. The spiral twisting is consequently a useful variation of shape. The A-alne 

 of the strf)ng ridges has already been spöken of. If a kudu has pierced a foe Avith the 

 shar]) points of its horn and then raises its head tlie greatest breaking power aifects the 

 bases of the horns and it is of course considerable as the levers are long. The horns 

 are, however, very firndy atta.ched to the skull by means of ver}' thick and eompact bony 

 tissue (lig. 11). In a not yet fullgroAvn s]:)ecinieM, the horns of which measure about 79 

 cm. in a straight line from base to tip, the basal compacta of the core under the sinuous 

 po]'tion is 22 nuii. thiek, and the Avalls bordering the »sinus» are of nearly the same 

 thickness. This ma}' be (|Uoted as an example of the solidity of structure exhibited by 

 these horns. The ureatest basal diainetei' of the lioni in the sau^ittal nlane is about one' 



