316 Mr. R. I. Pocock on 



giving off a short branch between the eyes. The 

 centre of the diamond might thus be described as 

 consisting of a pale strijDC above and below, and a 

 black stripe in the middle where the symmetry is broken 

 by the supernumerary branch. But in reality the pale 

 median line traverses the diamond from end to end. 



8. E. quagga Selousi (type in B. M.), — Two pairs of 

 symmetrical black stripes and a single short isolated 

 black stripe in the middle. 



These facts prove that amongst the Burchell's or Bonte 

 Quaggas the central line of the facial diamond may be 

 either pale throughout or dark throughout, or dark on the 

 forehead and pale on the nose, or pale on the forehead and 

 dark on the nose, or pale in its upper and lower extremities 

 and dark in the middle. 



The animals above described were not in any way selected 

 to prove or disprove a case. They were the first that 

 came to hand when I wished to verify, in the readiest 

 manner possible, the statement as to the colour of the central 

 line of the diamond. The arrangement of the bars is some- 

 times quite simple, sometimes very complicated and requiring 

 the greatest care to follow out with accuracy. Nevertheless, 

 an attempt at symmetry is generally traceable, although the 

 actual middle line of the diamond may not lie in the middle 

 line of the face. 



The exj)lai)ation of the facts given above is, I believe, as 

 follows : — 



The forehead and nose were originally furnished with a 

 large number of symmetrically disposed stripes, the median 

 line therefore being pale. By fusion these stripes are 

 reduced in number. When the fusion is regular the sym- 

 metry is retained ; when irregular it is destroyed. When a 

 dark stripe occurs in the middle line it may result from the 

 fusion of the two original admedian stripes. This, I under- 

 stand, is substantially Prof. Cossar Ewart's opinion. The 

 bifurcation of the stripes, however, may also be explained on 

 the hypothesis of the splitting of originally single broader 

 stripes. In that case there may have been a median stripe 

 on the forehead and head comparable to the spinal stripe in 

 the middle of the back. But in any case 1 am persuaded 

 that it is impossible to make the presence or absence of a 

 dark median line a basis for splitting the Quaggine from the 

 Burchelline species of Equus. 



(2) Mr. Lydekker also believes the " Quaggas '^ may be 



