460 THE ORIGIN OF THE LIBYAN HORSE [CH. 



that the hybrids have not reverted to a remote ancestor, but 

 rather to the immediate ancestor of the North African horses, 

 with the blood of which Biddy, the three-quarters bred Irish 

 mare, the well-bred Island of Rum pony, and the South 

 American mares were saturated. We have just seen that 

 beyond reasonable doubt there is a special tendency to exhibit 

 zebra stripes in the Libyan horse and its descendants, whether 

 they be in the Pampas of South America or in Kattywar, 

 Tibet, or the Malay Archipelago. It is therefore not im- 

 probable that Prof E wart's hybrids show stripings closely 

 resembling those of the zebra of North-eastern Africa instead 

 of those of their sire because their mothers had in their veins 

 more or less of the blood of the North African horse, which has 

 retained or developed a tendency to stripes resembling closely 

 in size and distribution those of the Somali zebra under con- 

 ditions somewhat similar to those under which have arisen the 

 stripes in the latter animal. The reader however will remember 

 that it was shown (p. 80) that although the plan of marking in 

 the Somali zebra represents the oldest type amongst zebras, it 

 by no means follows that the peculiar markings of the Somali 

 zebra represent the original livery of the common ancestor of 

 horses, asses and zebras. 



A simple experiment seems to confirm this view. I mated 

 a Muscovy drake ' Hans ' (a gift from my friend Dr Gadow) 

 with a common white Aylesbury duck. The Muscovy is, in 

 spite of its name (which is a mere corruption for musk), a 

 South American species, whilst, as is well known, the Aylesbury 

 is derived from the Mallard or common wild duck. The 

 progeny^ eight in number, resemble clearly in their colouring 

 the Mallard, each showing the colouring of the corresponding 

 sex in the wild ancestors (Fig. 134). But it will hardly be 

 maintained that the colouring of the hybrids, which proved 



1 My hybrids have proved absolutely sterile, though they paired off at an 

 early age. The ducks did not lay a single egg, and a Pekin and an Aylesbury 

 duck mated with one of the hybrid drakes did not produce a single fertile egg. 

 One of the ducks was examined after death, and showed only vestigial ovaries, 

 though a drake similarly examined had apparently the organs of reproduction 

 fully developed. 



