18 EINAR LÖNNBERG, STUDIES ON RUMINANTS. 



funiishes a great number of valuable informations in this inatter. In the work quoted 

 we find among others the following statements. Gazella picticaudata (Hodgs.) has its 

 horns »raiich compressed laterally, very closely ringed». They are thus strengthened for 

 use in the vertical plane. The horns of G. przevalskii Buchn. are also »much compressed 

 laterally. In G. granti the »section at the base is a long oval» and those of G. petersi are 

 »similar». With regard to other species as G. cuvieri, spjekei, pelzelni, thomso7ii^), vihorr 

 and allies it seems, as if the figures should indicate a similar, compressed condition. 

 Exceptionally as in G. soemmeringii the horns are said to be »nearly circular in section». 

 But it is to be observed, that in this form the horns »curve widely ontwards» and have 

 their tips again »abruptly hooked inwards so as to point almost directly towards each 

 other». With such a shape the horns must be used difiPerently than in such gazelles, the 

 horns of which extend chiefly in the sagittal plane. The horns of Lithocranius, which is 

 related to the gazelles, are also »oval in section» and »very closely ringed» just as in the most 

 gazelles. The, with the gazelles related, Antidorcas euchore has also horns of a similar structure, 

 although some differences may be mentioned. The horns ai'e lyrate, basally curved backwards, 

 then outwards and again with the tips inward or backward (as in the specimen at hand). 

 Measured along the curve the special object for the investigation measures about 38 cm. and 

 is provided with about 24 rings. These surround the horn completely. Distally the thicke- 

 nings are largest behind, in the middle on the median side and basally in front. This is due 

 to a rotation of the horn half a turn round its axis. The direction of this rotation can 

 be ver}? easily observed by following the longitudinal fibres of the horn from the base 

 and distally. To anybody doing this it becomes perfectly evident that the twisting of 

 the horn in this case has taken place in a direction quite opposite to that in other forms, 

 hitherto described {Tragelaphus, Strepsiceros, Oreas and Antilope), namely from the lateral 

 towards the median side, that is in the right horn a right handed spiral and in the left one 

 a left handed spiral. This is of remarkable interest. The horny sheath is, as can be seen 

 on a longitudinal section, thicker behind than in front, except quite basally. At the 

 upper end of the sheath the wall is a little thicker on the anterior side, but through 

 the greater development of the rings posteriorly the strength may be equal. Laterally 

 at the base the sheath is weakest. The core extends throuiih a little luore than 60 % 

 of the entire length of the horn. The raost striking feature of the core of Antidorcas, 

 when compared with that of the gazelles, is perhaps the presence of a large, almost 

 undivided (Conf. Pl. I fig. 7) air sinus in the base. This basal sinus of the core, which 

 of course is bordered by walls of compact bony tissue, has a situation which reminds one 

 of the one occupied by the basal portion of loose spongiosa described above from the 

 cores of the gazelles. It is also easy to understand, that such a loose spongiosa as the 

 one mentioned may give place to a sinus, because it has no mechanical functions and 

 may therefore be retrenched. The compact walls of the basal sinus of Antidorcas are 

 thicker posteriorly than anteriorly, and in addition to this braced by bony lamellfE. The 

 next third of the core above the sinus consists entirely of a rather firm and dense bony 



^) It is of interest to iiote that the females of this species have horns, which are »rudimentary», »about 

 the thickuess of a ccdar pencil'> and so »frail^ that »a very slight bkiw will break or knock oti' tliese horns». 



