TRANSACTIONS OF SECTION D. 591 
gametic coupling of distinct characters, interaction between characters in zygote 
(such that the second character is not manifested unless the first be also present), 
resolution, disintegration, &c. Such cases require minute analysis, and several 
generations may be needed to elucidate them. 
In tracing the laws of heredity in garden stocks several such complications 
are met with. 
(1) Susface character—hoary or glabrous.—Hoariness is dominant, glabrous- 
ness recessive. Simple experiments in the form DRx DR or DRx Kk, where 
D is the white-flowered form of Matthiola incana, and R, a glabrous ten-week 
strain, give normal Mendelian ratios in F,. 
In other cases the result as regards hoariness and glabrousness is more complex 
owing to the different behaviour of various glabrous strains, which, as far as 
can be seen, differ only in flower colour. Matings between two sap-coloured 
recessives, e.g., red glabrous and purple glabrous, give, as expected, glabrous 
offspring ; but the union of the two non-sap-coloured recessives (white and cream), 
or of asap-coloured and a non-sap-coloured (red o7 purple x white o7 cream) gives 
offspring all dominant (hoary), though both parents were glabrous. Similarly, 
when R,xR, are recessives of different colours the unions DR, x DR, and 
hae x R, give no recessives if either of the recessives used is a non-sap-coloured 
orm. 
(2) Flower-colow.—Various combinations of colours give reversionary purple 
in F,. Purple F, may also be produced by two white parents if they belong to 
strains differentiated by leaf-surface. Such purple cross-breds may give a 
simple Mendelian result in F,, or a variety of new-colour forms may appear. This 
latter result is commonly seen when cream is one of the parental colours. 
In the case (A), white incana x cream glabrous, F; is purple hoary. F,, shows 
the cross-bred and parental colours (purple, white, cream), and, in addition, three 
new forms, viz., red, red with cream eye, purple with cream eye. Again, in the 
case (B), glabrous white x glabrous cream gives at least nine colour-forms in F,,. 
In both cases the glabrous recessives are all either white or cream. But as the 
glabrous collectively constitute in case A one-quarter of the whole generation, and 
in case B presumably one-half, it is evident that the association of hoariness with 
colour depends on zygotic association and not on gametic coupling. Whether the 
appearance of these new forms indicates disintegration or simply recombination of 
‘pre-existing characters is still uncertain. Creams breed pure at once. Some 
whites are pure, others are heterozygotes with cream. The number of extracted 
recessive types resulting from a given union and their specific behaviours are not 
yet known. 
In the experiment last described we have to deal with (1) reversion in 
colour (2) reversion in a distinct character, leaf-surface; (3) interaction of the 
two characters in the zygote; (4) conceivably disintegration. The regularity 
with which all these phenomena occur plainly indicates that even these complex 
appearances result from a fundamentally simple system of Mendelian segregation. 
2. On the Result of Crossing Japanese Waltzing with Albino Mice, 
By A. D. Darsisuire. 
The Japanese waltzing mice used in this experiment exhibited the well-known 
restless and spinning movements; and, were it not for patches of yellow fur 
on the head and shoulders, and sometimes on the rump, they would be albinos— 
that is to say, they have a piebald yellow-and-white coat and pink eyes. According 
to my experience and information supplied by breeders, they breed true. With 
albinos everybody is familiar, but with the established fact that} they also breed 
true this is not the case. When an albino is crossed with a Japanese waltzing 
mouse, the offspring, in the majority of cases, is a mouse which on first inspection 
appears undistinguishable from the common house mouse. Sometimes there are 
white patches on the coat of greater or less extent than the grey; in a few 
instances the coat was yellow, and in a few others it was black or black-and- 
