KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 35, N:0 3. 23 



before. When »striking right and left» the Gemsbok must hold its head sideways. When 

 the horn with such movements has struck home and pierced the enemy, more or less, 

 and then the animal raises its head to its natural position or makes ready for another 

 blow, the pierced body makes resistance. The horn is then charged with a load or 

 pressure in the transversal plane, which is the more considerable, as the lever is long. 

 It is consequently a very usefiil mechanical adaptation to resist this transversal force that, 

 as is stated above, the section of the base of the horn is enlarged as well as strengthened 

 in the transversal plane. The great length of the horns is also not only less trouble- 

 some, hut even useful, when they are used in snch a manner, as sideways. Oryx betsa 

 is said to charge its enemy putting »its head low down between its forelegs, with the 

 horns pointed forward not much above the ground».^) The plane of attack is in such 

 a case the sagittal one, and the horns ought therefore to be strengthened in that plane. 

 I have not had the opportunity of seeing any horns of this species, but on figures and 

 plates it seems as if they were somewhat compressed, which would be an adaption to the 

 use in such a manner as stated above. In all species of Oryx the main mäss of material 

 constituting the horn is used for the forming of a tube whereby the horns are at the 

 same time made light and strong. 



The Alcelaplnne section of antelopes or subfamily Bubalidiiice is represented in these 

 investigations by Buhalis caaina and Connochoetes gnu. The peculiar double-curved horns 

 of the former have a very interesting structure. The horny sheath is thick, especially 

 on the convex side of each of the two curves, that is posteriorly in the proximal and 

 anteriorly in the distal curve. This stånds in connection with the fact, that it is just 

 stronger growth of the horny sheath at a certain place which produces the curving of the 

 horn in a direction opposite to the place of strongest growth. The transformation of 

 the core by means of reabsorption and apposition then takes place in accordance with 

 the new shape of the sheath and due to its pressure or non-pressure. The straight distal 

 tips of the horns consist to three fourths of their length only of solid horny matter. 

 On the anterior (convex) side of the distal curve there are several very strong trausverse 

 ribs on the sheath. Similar ribs, although not quite so strong, are also developed on the 

 lower side of the same curve where they also extend somewhat on the median side of the 

 sheath. On the concave (anterior) side of the proximal curve the same ridges are also 

 found and extend on the median side, sometiraes so far that they can be traced all round. 

 At the base the thickenings are strongest on the anterior side, but there reach entirely 

 around, forming rings. In other words the horny sheath is braced anteriorly and partly 

 on the median side by transverse ribs, which basally are extended to complete rings. 

 The core extends approximately through 65 % of the entire length of the horn. The core 

 forms two subequal curves, the proximal with the anterior outline concave, and the distal 

 with the anterior outline convex. The base of each core is formed by a large tubelike 

 prolongation of the frontal sinuses. These great tubes are provided with walls of compact 

 bony tissue, and basally both tubes are united along the median side, whereby the power 

 of resistance is increased. It is by these frontal prolongations that the head of the caama 



^) D. G. Elliot quoted b)' SoLATER and Thomas 1. c. p. 69. 



