264 J. L. Bonhote. 



(8) Notes on the colour of the eggs. 



(4) Reversion. — Where resemblances to other species are 



pointed out. 

 (o) Colour. — Where the attempt to show that hybridisa- 

 tion by breaking down the fixity of a species tends 

 to produce Variation, that this variation follows 

 without exception along certain definite tracts, 

 known as poeciloineres, and that it is from this 

 cause, and not from the usually accepted theory of 

 reversion that we get resemblances to other species. 

 It is pointed out, however, that the tendency of the sexes 

 to resemble each other may be due to a form of reversion. 



The appearance of White Coloration, which also follows 

 the lines of poecilomeres is commented on and ascribed to 

 lack of vigour. 



Explaxatiox or Plates. 



Plate IX. (M ^ S) *-* (P <^ M). 6 1st generation. 



Full plumage. 

 Plate X. Same bird as Plate IX. Eclipse plumage. 



Plate XI. P.M.S. g 3rd generation. Pull plumage. 



Plate XII. 

 fig. 1 . Breast feathers from pure Spot-bill £ . 



2. ì 



(Breast feathers from P.M.S. 6' (dark variety). 



! Eclipse plumage. 



4. Breast feather from adult Shoveler o . Intermediate 



plumage. 



5. Breast feather from adult Mallard. Eclipse 



plumage. 



' :- Breast feather from adult P.M.S. ? (dark variety). 



8. Breast feather from adult Shoveler ç . 



Series of Flank feathers showing- in successive generations 

 the approach towards $ type of feather, as well as resem- 

 blance to a Wigeon. All from birds in full plumage. 



9. From tr igen P.M.S. Ist generation. 



10. From pure Wigeon g . 



11. From trigen P.M.S. 2nd generation. 



12. From trigen P.M.S. 3rd generation. 



13. From pure Pintail Q . 



