34 - 



basally and in front. It is extended in the frontal (tranversal) plane and converges 

 with the anterior wall of the core in such a way, that its distal end becomes confluent 

 with the wall about lV'2 or 2 cm. from the base. On the sides it also reaches the walls 

 of the core. The other one is much larger. It is also extended in the transversal plane. 

 Its proximal free end is situated at the end of the first proximal third of the sinus. 

 From there it continues almost parallel with the posterior wall of the sinus for 4 — 5 

 cm., then curves backwards, converges and becomes finally confluent with the posterior 

 wall in the upper fourth of the sinus. The sides of this lameliar trabecula is all along 

 soldered to the outer wall of the core. Both these lameliar trabeculae thus form with 

 the walls of the core a kind of, at their proximal end open, pockets. In more strongly 

 developed cores there are in addition to these on the anterior side a number (3 to 6 

 or more) lameliar trabeculae parallel with and of a similar construction as the first de- 

 scribed, but situated higher up on the anterior wall (conf. tig. 14 b Pl. II). Sometimes 

 these are, at least partly, almost as strong as the basal one, in other cases they are 

 merely indicated by low ridges. Likewise there might be one or two additional posterior 

 trabeculae near the base of the core. If we compare these constructions with the law of 

 tension, it becomes evident that the lameilar trabeculaa of the anterior side agree with, 

 and are to be regarded as the ends of the trajectories of pressure in accordance with 

 Culmann's law, although they are not developed on the other side of the neutral axis. 

 In the same way the trabecute on the posterior side might be considered as representing 

 the trajectories of stretching. The distal tip of the core above the sinus consists of 

 spongious bony tissue, surrounded by an exteriör compact layer. In this spongiosa there 

 cannot be detected any special mechanical arrangements of its elements. In some in- 

 dividuals it forms a network with longitudinally extended meshes, in some others it is 

 almost tubular. The core is obliquely compressed from the sides. The mesial surface 

 is almost flat, the lateral convex. The shape of the horny sheath is still more com- 

 pressed, because it develops in front a very prominent edge, otherwise its outlines corre- 

 spond to those of the core with a flat mesial and a convex lateral side. It is more or 

 less transversally striated or wrinkled, and in some places the anterior edge forms pro- 

 truding knöts, a little thicker than the edge itself. The goats use their horns to some 

 extent in the same way as the sheep, but it is not only the most basal parts which are 

 used in butting by the former. The frontsides with their edges strike a blow like a 

 stick or a club. ^) The horns are consequently subjected to a pressure and breaking 

 force in the sagittal plane. The whole construction of the horns is plainly adapted to 

 withstand such a force. The compression from the sides (»Verlängerung des Querschnittes») 

 bas a strengthening effect in the sagittal plane (the plane of attack) with retrenchment 

 of material. The violence in the act of butting strikes most energetically the anterior 

 side of the horn. This is therefore strengthened by the thick frontridge of the sheath, 

 the anterior wall of the core is thicker and is braced by the trabeculte described above, 

 which represent the trajectories of pressure. m';!,, ';!t '.ii 



,, ,.. ^ :,,• ,t,..., ,-■ ■.:.'.,'l : Ka // I ' 



^) The tips of the horns are only used, when the animals want to scratch themselves, and for such 

 movements there are of course not needed any mechanical strengthening arrangements. 



