KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 35. N:0 3. 11 



spongiosa are to be seen and these extend especially ovei' soine i)arts of tliu median and 

 posterior sides. A similar tissue is also develöped in the tip of the core. In addition 

 to this small portions of spongious tissue extend into the interiör of the siniis in some 

 places.^) From this description it may be concluded that the main strength of the horn 

 of the eland lies in the horny sheath, the core being comparatively weakly built. Sufticient 

 power of resistance, which is needed especially when the horns are used as levers, is 

 gained in this case, in spite of the weakening of the core, by enlarging the diameter 

 of the tube ^) of which the horn consists, and by increasing the thickness of the walls 

 of this tube by the sacrifice of the tirmness of the central axis. This is in accordance 

 with the thesis expressed in the beginning of this treatise that increased power of re- 

 sistance is gained by arranging the resistant material peripherically as far as possible 

 from the neutral axis, on the condition that there is no risk of corrugation of the tube. 

 In this case, however, the horny sheath has become enough thickened so tha,t it cannot 

 be any danger of that kind. In addition to this it is steadied by the compacta of the 

 core and the spiral ridges are also useful in preventing such an accident. By this con- 

 struction material has to a great extent been saved in the core, and at the same time 

 the weight of the core has been considerably lessened especially by the development of 

 the large distal cavity. It can thus be said that the development of the horn of the eland 

 has gone in a direction to some extent parallel with that which has taken place in the 

 development of the horns of the most specialised among Bovidce nainely the genus /io*'. 

 Tlie distal straiglit part of the horn including the great distal sinus of the core reminds 

 one of a horn of Bos. In the spiral twisting of the proximal part with its ridges we 

 may see decided affinities to the antelopes related to Oreus and an inheritance from the 

 nearest ancestors. It might also be remarked here that the elements of the horn of the 

 eland are quite straight in the distant part where no ridges are develöped and the twisting 

 , begins simultaneously with the development of the ridges. This might speak for a cau- 

 sality between ridges on the horn, and a spiral twisting of the same. The straight horn 

 is of course the most original and primitive. 



Of the Cervicaprinw I have had material of two species, thanks to the kindness 

 of Professor F. A. Smitt. Both these show conditions which may be regarded as rathcr 

 primitive. The sharp and slender horns of Pelea capreolus remind one of the horns of 

 Cephalophina: although they are longer. The horny sheaths are comparatively very strong. 

 The proximal half is provided with highl}- develöped rings which especially a^t the base 

 are sharply prominent. The distal part of the sheath is smooth although some faint 

 annular thickenings may be traced. Not even the basal part of the sheath is weak as 

 may be judged from the fact that the two proximal rings measure about 3 mm. in section 

 and the third from the base 4 mm. The core extends throuffh 57 % of the entire length 

 of the horn in the specimen at hand. It is compressed from the sides thus gainiug strength 



^) Vrolik has made some. remarks about the horn of this aiiimal in Verb. d. Kon. Akad. van Wetenschapp 

 Amsterdam 1854, »Över het Verschil van de inwendige Gesteldheid der Hören pitten bij Antilopen» and also given 

 a figure (Taf. II) but no detailed description. 



^) The diameter of the base is about 10 % aud the diameter at the middle of the horn is more than 

 7 '/o of the length of the horn. 



