42 EINAR LÖNNBERG, STUDIES ON RUMINANTS. 



Altliongli the parallelisms in the development of these orofans are numerous, as is 

 already stated, the horns cannot be denied all taxonomic value, because really related 

 forras are also, of course, to a certain degree similar in their development. The inter- 

 pretation of the phenomena must, however, be made with care, so that parallelism and 

 real affinity is not mixed up. Such a series as that exhibited by Trag el aphus, Strepsiceros 

 and Oreas must be regarded as a very natural one. All these forms have their horns 

 more or less triangulaT in section, strengthened by longitudinal ridges or thickenings, 

 twisted on their own axis or forming an open spiral, but devoid of knobs and rings. 

 These characters of the horns are supported by a great number of other characteristics 

 so that it can safely be asserted that the mentioned three genera form one of the most 

 natural groups among the antilopes. ^) The large lachrymal iissures, the brachydont molars, 

 little developed frontal sinuses together with some other features which are especially pro- 

 minent in the two first mentioned of these three genera as, for instance, the peculiar 

 pattern of colouration similar to that found in some Cervicornia, the compactness of the 

 core ^) and its great length compared \vith that of the horny sheath, which latter is com- 

 paratively thin, etc., make it probable that this subfamily includes rather primitive forms. 

 But even within this series the summit of the development is constituted by antelopes 

 offering a certain bovine appearance, Oreas. Contrary to the condition in the other genera 

 even the female of the eland is provided with horns, the horny sheath forms a compara- 

 tively larger and stronger tube and the core can therefore have its central parts reabsorbed, 

 so that an interiör cavity is formed. Notwithstanding this, there cannot be the slightest 

 doubt that Oreas is a raember of the Tragelaphine series. 



The horns in the subfamily Antilojnnce are rather varying in shape but have a 

 common feature, the smooth transverse ribs or rings, which perhaps are better and more 

 typically developed in this than in other groups. In Cervicaprinse, too, the rings are, 

 however, well developed. It is a feature common to the members of this latter group, 

 that they have the horns more or less curved forward, at least at the tips. But also 

 among the Antelopince there are several forms with the extreme tips curved forward 

 (e. g. Saif/a and some gazelles) and in the aberrant dibatag {Ammodorcas) the whole 

 horns form a curve with the concave side anteriorly. They resemble thus, with regard 

 to their general shape, the horns of some species of Cervicapra. It is evident that horns 

 Avith forwardly directed tips must be used in a somewhat different manner than recurved 

 horns. But, on the other hand, it is possible that the curving forward can originate 

 independently in ditferent forms from a straight horn, so that the fact that the horns of 

 two animals are curved in a similar manner is no proof that the animals stånd in genetic 

 connection to each other. It does not, however, seem probable that antelopes which have 

 got the tips of their horns recurved, låter in the chain of development change the direction 

 of the curve to the opposite, or, the contrary, that a forward curving is changed to a 

 backward one. That is, since a differentiation has taken place in a certain direction and 



■') Whetber Boselaplius may be counted in the same group, as has been doae by Flower and Lydbkker 

 I do not know, because I have not had any material of the nilghai, but I have some doubts about this. 



^) The consistency of the core of the kudu may favourably be compared with that of the antiers 

 of a deer. 



!'.il .' 



