16 The Journal of Heredity 
No. 1543, has a black patch on the 
throat and another on the nape, while 
the auriculars are blackish and the inter- 
mediate region of face and neck white 
or buffy. The tails are all barred, but 
not coarsely, while the narrow black 
streaks on the rump show well the 
pattern of the principalis male. These 
birds, therefore, show very little in- 
fluence of the Reeves female. Compar- 
ing them with our one female specimen 
from male ring-neck x female Reeves, 
the corresponding cross made in 1912, 
they appear entirely different. This 
female (No. 448) has no trace of male 
plumage. She corresponds very closely 
to the J females of 1914, but she is much 
larger than any of them. 
FEMALES ARE SEXLESS 
Sex Glands.—Perhaps the greatest 
surprise of all was the failure to find 
any trace of germinal tissue in any of the 
females of either cross. All suspicious 
tissue from the proper region was fixed 
and sectioned, but the results have been 
entirely negative. These sexless birds 
are called females on the strength of a 
small and flaccid oviduct, normally 
placed and present in all cases. 
Turning to the males, I find that there 
is no trace of a reciprocal difference as 
occurred in the Reeves x ring-neck cross 
of 1912. Both crosses are darker in color 
than the darkest cross of 1912 (male 
ring-neck x female Reeves). This fact 
may be explained by the generally 
darker tone of Prince of Wales males as 
compared with ring-neck males. The 
tails are always barred, unlike the male 
Reeves x female ring-neck cross of 1912. 
The ground color of the central tail 
feathers is darker than that of the 1912 
cross and the backs, scapulars and rumps 
are more uniform. No other differences 
are apparent, the presence or absence 
of neck-ring having no apparent effect 
on the pattern of the hybrids. 
All the males of the 1912 and of the 
1914 crosses are similar in size. The re- 
ciprocal difference of male plumage 
described for the 1912 cross is trifling 
as compared with the wide size and 
pattern differences in the females of 
the 1914 cross. 
Summary.—In the 1914 cross, Reeves 
male x Prince of Wales female (cross J) 
and in the reciprocal cross Prince of 
Wales male x Reeves female (cross K), 
the sterile male hybrids are similar and 
closely approximate the slightly dif- 
ferent reciprocal hybrids of the Reeves 
xX ring-neck experiment of 1912. With 
the females, however, of the two first- 
mentioned crosses, there are almost no 
points in common. In cross J they are 
shown to be small, fémale-like,*»and 
very close to the Reeves female in their 
coloring. In cross K they are large 
and male-like, with pattern and coloring 
of both the male parents. No trace 
of a sex gland was found in any of 
these females, but a small and thin- 
walled oviduct was always ‘present. 
These facts are simply given for what 
they are worth. The writer does not 
feel competent to enter into a discussion 
of their possible significance. It is 
possible that they may be explained on 
the basis of sex linkage, with the as- 
sumption that the eggs are dimorphic 
and the sperms monomorphic for sex 
and sex linked characters, but no proof 
is available on account of the impossi- 
bility of testing the sterile hybrids. 
The most suggestive point about these 
hybrids seems to the writer to be the 
Reeves-like appearance and puny size 
of the females when the male Reeves 
was used as a parent. It would almost 
seem as if gametes bearing Prince of 
Wales characters had been kept apart 
in producing these females. Their ex- 
tremely small size led to a question as 
to the size of their somatic cells. 
Rough measurements of their spleen 
cells made for me by D. H. Wenrich 
failed to reveal any difference of this 
sort between K and J females. Ob- 
viously the chromosome count would 
be of great interest in this case also. 
The absence of ovarian tissue is another 
curious feature which demands further 
experiment to verify completely. 
