KONGL. SV. VET. AKADEMIEISfS HANDLINGAR. BAND 35. N:0 3. 47 



I have had the opportunity, since the above was alreadj^ written, of studying 

 the structure of the horn of Damaliscus pygargus. The horn is strongly compressed from 

 the sides in such a way that the section becoraes ovate with the broader end anteriorly, 

 which is an arrangement tending to strengthen the horn in the sagittal plane (T beam). 

 The proximal two thirds of the horny sheath are provided with strong annular thickenings 

 which are most defined on the front surfjxce and thickest at the niiddle of the horn, 

 Avhere they form strong transverse knobs. These rings protect the sheath from being 

 corrugated. The thickness of the sheath betAveen the rings is from 3 mm. (proximally) 

 to 6 mm. (distally) on the anterior side, but on the posterior only from 3 to 4 mm. resp. 

 The horny sheath is thns much more strongly developed on the anterior side. D. pygarqus 

 differs in this respect from Buhalis caama. This might stånd in correspondence with 

 the different mode of curving of the horns of these two animals. In B. caama the 

 posterior side of the horn is strained in the act of hooldng and it is thus appropriate 

 that the elastic sheath is strengthened posteriorly. D. pygargus which has the tips of 

 the horns somewhat recurved must iise its horns in a diflPerent manner, and the anterior 

 side is the strained oue. The sheatli is therefore in this case strengthened anteriorly. 

 This feature also agrees with the general shape of the horn, the section of which is ovate 

 with the broad end anterioi-ly, as is alluded to above. 



The core of D. pygargus extends through 57 % of the entire length of the horn. 

 About one sixth or more of the core, basally, is occupied by a large undivided sinns 

 which is a prolongation of the frontal sinus. The posterior wall of this sinus is quite 

 compact and about 4 mm. in thickness. The anterior wall is fully twice as thick, but 

 less compact. The core above the sinus is spongious. The peripherical layers are more 

 den se, posteriorly almost or quite compact. Peripherically the elements are longitudinally 

 extended. The central parts of the core consist of a rather loose spongiosa with large 

 irregularly roundcd meshes. In this trabeculaj according to Culmann's law may be traced, 

 although they are not very conspicuous (Pl. II tig. 17). Distally the arrangement partly 

 becomes almost tubular, but in the extreme tip it is rather irregular. The core of D. 

 pygargus is thus by far not so strongly built as that of B. caama. The structure of the 

 former can be said to be, to a certain extent, interraediate between that of the latter 

 and the same in the gazelles and shows also some resemblance to the structure of corre- 

 sponding parts in Antidorcas. This is of interest, because the shape of the horns of D. 

 pygargus reminds one of that in the gazelles and the springbuck, and must be used in a 

 similar manner. The correspondence between the shape and mode of using the horns 

 and their structure is rendered still more evident by this exaraple. 



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