518 Mr. R. I. Pocock on the 



intermediate in coloration between two specimens that have 

 been made the tj^pes of distinct subspecies, namely Gre^i a.nd 

 Lorenzi. 



In his account of the BurchelFs zebra in the Paris Museum, 

 Dr. Trouessart incidentally attempts to prove that the forms 

 named Burchelli and Chapmanni are specifically distinct from 

 each other. Under Chapmanni he includes the northern 

 form described as B'dhmi (=Granti) and presumably also 

 Selousi, Wahlbergi, and antiquorum. It is of no great 

 moment whether these forms be regarded as species or sub- 

 species ; but since a practically complete gradation in the 

 disappearance of the stripes from the fetlocks upwards to the 

 root of the tail can be traced from B'dhmi and Selousi through 

 Chapmanni^ TVahlbergi, and antiquorum to the various types 

 of Burchelli (sensu sfricto), it is illogical to draw a line 

 between Burchelli and Wahlbergi, classifying the latter with 

 B'dhmi and Selousi and letting the former stand alone. 



The distinctions upon which Dr. Trouessart lays stress are 

 the alleged absence of stripes upon the legs in Burchelli and 

 the presence of only narrow, faint, and incomplete stripes 

 upon the hind-quarters, beneath the last complete stripe that 

 runs from the root of the tail to the groin ("aine"). Contrasted 

 with this are the strong complete stripes on the hind-quarters 

 in Chajymanni and their extension at least as far as the hocks. 

 It is quite true that typical Chapmanni may be distinguished 

 from typical Burchelli by these and other characters ; but the 

 variation in the development and downward extension of the 

 stripes over the quarters in individual specimens of Burchelli is 

 very great. I have before me the photograph of a specimen 

 that formerly lived in the London Zoological Gardens. In 

 this there are only about two very faint and narrow stripes 

 below the one that passes to the root of the tail. The example 

 in the Bristol Museum * is also very imperfectly striped below 

 that line. This is also the case in an example that was living 

 in the Amsterdam Zoological Gardens a year or two ago. 

 Nevertheless the statement that there are no stripes on 

 the legs in Burchell's zebra is not true. Stripes are quite 

 commonly retained both on the knees and hocks; and by 

 publishing the photograph of the Burchelli preserved in the 

 Paris Museum, Dr. Trouessart has supplied additional and 

 conclusive evidence of the occasional extension of transverse 

 stripes — narrow and more or less broken up certainly — all 

 over the hind-quarters down to the level of the junction of the 



* For fig. and description, see Pocock, P. Z. S. 1903, ii. p. 196, and 

 Ann. & Mag. Nat. Hist. (6) xx. p. 41 (1897). 



