passent dans les ébauches des‘ cones et des batonnets et interviennent 
apres modification chimique, dans leur constitution. Il persiste de ces 
granulations d’origine plastochondriale dans le segment interne oü leur 
valeur est jusqu’ici inconnue. Dans le segment externe, ces grains 
forment une gaine finalement homogene au filament d’origine cen- 
trosomique. Le mode de formation de la gaine du segment externe 
montre la réalité de la striation transversale de ce segment et ex- 
plique son clivage en disques par les réactifs. 
Nachdruck verboten. 
Some Phenomena of Species Hybridisation among Pheasants. 
By GeorsE PerctvaL Muper, A.R.C.Sc. Lond. F.Z.S. 
Lecturer on Biology at the London Hospital Medical College (University of 
London) and at the London School of Medicine for Women (University of 
i London). 
A summary of certain results obtained by crossing Silver and 
Swinhoe pheasants may be of interest to students of Genetics as 
suggesting fresh lines of research. 
An examination of the skins of hybrids obtained by crossing the 
two species (Euplocamus nycthemerus x E. Swinhoii) shows that the 
analysis of the results is extremely difficult and the interpretation of 
the features of the hybrid plumage is not without possible pitfalls. 
A pattern may be exhibited in the hybrids which looks like a some- 
what similar pattern in one or other of the two sexes of the two 
parent species: but whether it represents the specific pattern or is 
a hybrid character simulating it, or whether it is a sort of dislocated 
mosaic with some of the unit-characters of the pattern of one sex of 
one parental species dominant, while other features of the pattern are 
dominant unit-characters from the other sex of the same species, or 
from either of the two sexes of the other parental species, is a prob- 
lem which will require answering for each special feature, by con- 
tinued experiment. It follows from considerations of this sort that 
unless the alternative feather patterns and colours with which the 
investigator is concerned, are very strongly marked and divergent, 
and each represents a single unit-character, or a combination of unit- 
characters gametically coupled together, great caution is necessary in 
making definite or positive statements even of the most seemingly 
