REVERSION IN HYBRIDS 331 



Fowls and of Pigeons which were all devoid of the 

 ancestral colours, as related in his admirable but 

 rather neglected work, " Variation of Animals and 

 Plants under Domestication." 



Now and then hybrids between species have 

 been produced showing an extraordinary likeness 

 to some species allied to, but distinct from, the 

 two forms concerned ; the classical instance of 

 this is that of the two Sheldrakes bred at the Zoo 

 many years ago between the little-known South 

 African Grey-headed Sheldrake (Gasarca cana), 

 which much resembles the Ruddy Sheldrake, and our 

 common Sheldrake ; these resembled the Australian 

 dark grey Sheldrake (Casarca tadornoides) far more 

 closely than either parent. These birds are to be 

 seen at the South Kensington Museum. At the 

 Zoo lately, also, was a cock Pheasant presented by 

 Mrs. Johnstone, the first importer of the Formosan 

 black Mikado Pheasant (Calopbasis mikado), and 

 bred between that bird and the copper- and- white 

 Elliot's Pheasant (Phasianus ellioti) of China, 

 which, except for rather different breadth in the 

 bars on the tail, was identical in plumage with 

 a third species, Mrs. Hume's Pheasant (P. humite) 

 of Manipur ; a form far less specialized in coloration 

 than either of the other two, and very likely ancestral 

 to both, just as the dark grey Australian Sheldrake 

 no doubt represents an ancestral form of these 

 Ducks, generally so strikingly and showily coloured. 

 Rarely does a hybrid between distinct species 

 follow almost exclusively one parent in coloration. 



