8 



ARKIV FÖR ZOOLOGI. BAND 6. NIO 10. 



of of the two components of the spiral is more reduced than 

 the other, it must assume a straighter course than the other, 

 and if the spiral at the same time is flattened into an nndu- 

 lated curve running in the vertical plane alone, it must be push- 

 ed to one side or the other, just as leaf the right as the left. 



The shape of the penis of Tragelaphus is thus to be 

 regarded as a result of a reduction from the original type 

 of penis exhibited by primitive ruminants without any addi- 

 tional modification. There is no cushion-like thickening, no 

 processus urethralis is formed as in so many other Antelopes 

 etc. The Bushbuck is thus in this respect different from 

 other Antelopes and stånds rather isolated. 



Garrod (1) has 

 a very short note 

 about this genus 

 saying: »Tragela- 

 phus {scriptus) dif- 

 fers but little from 

 this [Nannotragus 

 = Ourehia nigri- 



caiidata, (conf. 

 above the descrip- 



tion concerning 

 this species)], ex- 

 cept that the end of it is slightly turned upwards.» The reduc- 

 tion appears thus to be still more advanced in that species 

 of Bushbuck, but otherwise there is nothing in Garrod's note 

 which speaks against the remarks made above concerning 

 the somewhat isolated position of the Busbucks with regard 

 to this organ. 



Or 



Fig. 7. 



Penis of Poephagus, a. obliquely from the 

 left side ; b. front view. 



The penis of tlie Yak. 



As might be expected, the penis of the Yak (Poephagus 

 grunniens) exhibits the »bovine» type. It shows neverthe- 

 less very distinctly some features which prove its derivation 

 from a more ancestral type with »ovine» characteristics. 



The accompanying figure (fig. 7) illustrates this very 

 plainly. The cushion is very w^ell developed and the free 

 processus urethralis has still considerable dimensions even if 

 it does not project beyond the end of the penis. A reduc- 



