76 THE EXISTING EQUIDAE [CH. 



specifically distinct, and he includes all the varieties of the 

 Burchell group as well as the true quaggas under the species 

 Equus quagga. On the other hand, Mr Lydekker supports 

 the older view that the Burchell Zebra and the quagga are 

 specifically distinct, on the grounds that (1) the pattern on 

 the forehead of the quagga forms a shorter and more regular 

 diamond than in the Bonte Quagga, and that in the former 

 the centre of the diamond is a pale stripe with four or five 

 dark stripes on either side of it, whereas in all Bonte Quaggas 

 or Burchell's Zebras the diamond is made up of from five to 

 nine stripes, the middle line being black with from two to four 

 stripes on each side: and (2) that quaggas may be distinguished 

 from Burchell's Zebras (Grant's, Crawshay's, Chapman's, and 

 the typical Burchell's), by the presence on the skull in front 

 of the orbit of a depression claimed to be the remains of a 

 pit which in the case of more archaic forms lodged a facial 

 gland. 



Mr Pocock replies by showing that Mr Lydekker's first 

 proposition " is not in all cases true either of the ' quaggas ' or 

 the ' Burchell's Zebras '," and against Mr Lydekker's second ob- 

 jection he urges that the depression noted in two quagga skulls 

 " belongs to the category of characters likely to appear sporadi- 

 cally as atavisms," and he maintains that " such characters are 

 of doubtful value as a basis for the formation of natural groups'"' ; 

 he points out that Mr Lydekker has not cited a single skull 

 of a true Burchell Zebra, and shows that " although the skulls 

 of the female Grant's Zebras [in the British Museum] have 

 practically no trace of the depression, it is very perceptible 

 both to eye and touch in the skull of the stallion." These 

 questions therefore still remain sub judice, but it is manifest 

 that whether the Burchell's Zebras and the quaggas of Cape 

 Colony were specifically or sub-specifically distinct, the relation- 

 ship between them was extremely close. 



The testimony of most competent observers is unanimous in 

 stating that the quagga was the best adapted for domestication 

 of the striped Equidae, as is proved by the fact that the 

 colonists not unfrequently kept tame quaggas to run with their 

 herds of horses, since the watchfulness of the former was a 



