KONGL. SV. VET. AKxiDEMIENS HANDLINGAR. BAND 35. N:0 3. 33 



core is firmer on the latter side. To withstand violence from the sides in the trans- 

 versal plane there is no special adaption visible. It is also well known that the rams in 

 butting only use their foreheads and the bases of their horns. Herein a considerable 

 energy is developed, but all this force works in the sagittal plane, that is just the one in 

 which, as is shown above, the horns are strengthened. The position of the horns and 

 their shape make the use of their tips impossible and the horns can just as little be 

 used as levers. It is thus almost exclusively the basal parts of the horns which are put 

 to a test. The distal part of the core has only to carry the dead weight of the horn 

 and for that purpose no special mechanical arrangements are needed. 



The horns of the wild sheep are generally much larger and more strongly developed 

 than those of the tame ones. Their power of resistance is especially increased by their 

 great basal width. They may, however, be said to be of the same general type as the 

 normal horns of the domestic sheep, at least as far as the true sheep of the Caprovine 

 group are concerned. They are triangulär in section and thus strengthened after the 

 same plan as those of the common sheep, although the curving and the superficial armature 

 may differ in different species. Ovis vignei cycloceras has, for instance, to quote Lydekker^) 

 »the two front ridges very strongly developed and forming distinct nodose beads, between 

 which the front surface of the horn is concave and carries böld and widely separated 

 transverse wrinkles» (1. c. p. 172). We are informed by a quotation in Darwin's »Sexual 

 Selection» that these animals know how to use this armature when butting and that a 

 ram of this species attacking a domestic ram caught the latter »across the face and nose 

 with a sharp drawing jerk of the head.» The movements are however made in the same 

 plane as usual and the general mechanical arrangements in order to strengthen the horns 

 are consequently the same. The rams of Ovis ■poli seem, however, sometinies to use 

 their horns in a manner aberrant from the usual one. Lydekker (1. c. p. 195) quotes 

 Viscount E. de Ponons about the habits of this animal and there we read that fighting 

 males of this species butt each other »exactly as sheep do», but also that they sometimes 

 run »alongside each other striking sideways against the ribs and flanks». Such movea)ents 

 can in this case be effective because the points of the horns are »at right angles with the 

 line of the neck.» This shape of the horns and their spiral twisting are however such 

 that the shock also in this case strikes the tip of the horn in the same direction as that 

 of the longest axis of the section through the strongly compressed horns. ■^) There is 

 consequently but little risk of bi'eakage. 



The structure of the horns in the genus Caprn is quite different from the same 

 in tlie genus Ovis as well with regard to the core as the shape of the sheath. In the 

 common goat the sinus often extends through more than three fourths and at least 

 through fuUy one half of the core. The walls surrounding this sinus consist of compact 

 bony tissue which is considerably thicker on the anterior side. In the most weakly 

 constructed horn cores of this kind, I have seen, there are only two bracing trabeculte or 

 septa to be found in the whole sinus (conf. tig. 14 a). One of these is a lamella situated 



^) »Wild Oxen, Slieep and Goats of all Lands». 



^) Coiiipare the splendid figures of this animal in Lydekker's work quoted above Pl. XVI and textfigures 

 37, 38 and 39. 



K. Sv. Vet. Akad. Handl. Baud 35. N:o 3. 5 



