KONGL. SV. VET. AITADEMIENS HANDLINGAR. BAN7X 35. N:Ci 3. 15 



this case accordino-ly the same rosnlt is gained bj- the aiTangement of tlie inost resistant 

 material, withoiit alteration of the shape. The rings of the horiiy sheath are of coiirse 

 useful against torsion and corrugation and, because they ai"e not regnlarly and quite trans- 

 versally applied, also against breakage. The strengthening effect is specially great when 

 they are moditied into a spiral thickening. As can be concluded from the description 

 the horns of AnfUope are strong and powerfnl weapons which can be used not only 

 against rivals, but also against carnivorous enemies. The spiral twisting is decidedly 

 useful because it adds to the sti-ength of the hoi'n. The rotation is effected by raeans 

 of uneven growth which is also outwardly visil)le Vjy the rings which are always formed 

 on the originally anterior and median side which låter occupies the most peripheric part 

 of the spiral. The twisting takes place in the same direction as in the foregoing cases 

 from the inner towards the outer side, thus on the right side it is a left handed, and 

 OM tlie left a right handed spiral. 



A section through a core labelled A^pyceroft melampns shows that this is much 

 inore ^veakly constructed than that of Antilope. The greater distal part of the core of tlie 

 »Pallah» consists of a, very fine spongiosa. Near the tip this tissue in the present dry 

 state is so fragile that it almost crurables under the saw. Towards the middle of the 

 core it becomes firmer and the meshes are more decidedly extended in a longitudinal 

 direction which of course is a useful arrangement. Below the middle of the core the 

 structure assumes a greater likeness to that of the core of Saiga. Finally, near the base, 

 the peripherical la3^er becomes quite corapact. This compacta extends on the anterior side 

 nearlv through half tlie core. Postcriorlj' it is less thick. In the centre between these 

 compact Avalls there is a basal portion of spongious tissue, coarser than elsewhére. Great 

 canals for the main bloodvessels traverse the core in its whole length. These canals are 

 mostly found in the posterior half of the core. Quite basally an irregular sinus is found. 

 The core is compressed, but, thanks to a slight rotation of the horn, tlie longest axis of 

 a section through the core lies in and above the outward curve in the sagittal plane, 

 but, at the base more obliquely. This is of course suitable because a pressure applied 

 to the tip of the horn does not, depending upon the curved shape of the horn, affect the 

 basal parts in the sagittal plane, but obliquely outwards. The core is thus strengthened 

 in the plane of attack. It is evident that the core of the pallah is rather weakly built, 

 and it is with regard to its structure intermediate between that of Antilope and that 

 of (jazelln. The main strength of the horn of ^■Epyceroa lies in the horny sheath. I have 

 not had the opportunity of raaking any section through such a one, but an exteriör in- 

 spection confirms the opinion that the horn of this animal must be strong as well as 

 elastic. To its strength the development of transverse ridges contributes essentially. 

 These ridges are originaily developed on the median side of the base but through a slight 

 rotation of the horn, already mentioned above, they become situated on the anterior side 

 in the upper curve of the horn. This rotation takes place in the same direction as in 

 Antilope that is from the median towards the lateral side. The value and strengthening 

 effect of these ridges is increased by the fact that they are not i-egularly transversally 

 placed. Usually they are arranged in such a way that two (originally) latero-postorior 

 (distally autero-mediau) ridges correspoud to and are more or less eonnected with one 



