KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 35. N:0 3. 17 



is broken or at least wavy. The rings are also not quite transversally arranged, but the 

 anterior part of a ring forms usually a curve with the convex part directed downwards 

 like the letter U. At least proximally, the lateral ends of the rings are transversally 

 directed or even bent downwards. This ai'rangement of the cur^es, so that no section 

 can be laid throiigh the horn Avithout cutting one or more annuli, adds considerably to 

 the strength of the horny sheath and muoh more than if the rings had been regular 

 and lying in one plane. The cores are evenly curved backwards. As in the foregoing 

 specimen they are compressed from the sides with the basal diameters measuring resp. 

 29 mm. and 21 mm. There is a basal outer compacta, although less developed than in 

 the former specimen. The difference in thickness of this layer posteriorly and on the 

 sides is not so great in the male G. dorcas. The iiTegular spongiosa surrounded by this 

 basal compacta extends throngh a sixth of the core, more or less. Otherwise the core 

 consists chiefly of a distinctly tubular spongiosa (Corif. Pl. I. fig. 6). The tubes are, in this 

 case, larger and therefore more easily seen. In addition to this it seems as if the peripherical 

 compacta had corapletely disappeared, at least in front and on the sides. Posteriorly the 

 tissue is a little more dense and towards the tip more spongious. As in the foregoing 

 specimen the core extends through three fifths of the horn. It is evident that in both 

 these gazelles the mechanical adaptations are of the same type with the chief intention 

 of making the horns resistant in the sagittal plane. In spite of this the horns of the 

 gazelles are comparatively weakly constructed. They are nevertheless not only »ornaments», 

 but also used as weapons, although sometimes with disastrous effect to themselves. 

 Breiim writes about this in his »Thierleben»: »Die Böcke (gazelles) .... streiten sich so 

 heftig, dass sie sich gegenseitig die Hörner abstossen», and he adds, that he has shot 

 several specimens, »bei denen die eine Stange an der Wurzel abgebrochen worden war». 

 Fi'om this can be seen, that the base is the critical point, which of course was to be 

 expected, because the \iolence is greatest at the end of the lever, and the base also is not 

 protected by the horny sheath, which otherwise might contain the principal strength of 

 these horns. I suspect also, that these accidents have happened when the horns have been 

 subjected to some violent force from the side, for which they are not at all adapted. 

 The form of the horns with the tips directed forward indicates that they are intended 

 to be used for blows in the sagittal plane from above downwards. The whole structure 

 is adapted to such a purpose. If they are used in this manner, the anterior side becomes 

 the strained side and the anteriorly thickened horny sheath with its oblique annular 

 thickenings make theni able to withstand a very great amount of strålning. The posterior 

 side is the compressed one. The main part of this power falls on the core, but we have seen 

 that this organ is strengthened posteriorly by a greater development of the compacta in 

 these parts, in addition to the prolongation of the diameter of the core in an antero- 

 posterior direction. Against torsion the sheaths are strong enough on account of their 

 rings, but the core is weak in this respect as well as in withstanding blows from the side. 

 Although these investigations only comprise the forms mentioned above of the genus 

 Gazella, it can be concluded from the descriptions and figures in the zoological litera- 

 ture that inany other gazelles have horns, which show similar mechanical adaptations 

 to fhose already described. It is especially the magnificent »Book of Antelopes», which 



K. Sv. Vet. Akml. Uandl, Band 35. N:o 3. 3 



