472 
Human Spermatogenesis: T. H. MonTGOMERY, JR., 
University of Pennsylvania. 
The point was made that in man there are four 
types of probable functional spermatozoa, differ- 
ing in their content of modified chromosomes. One 
type has two of these bodies, one has none, one 
has the larger body only and the other has the 
smaller only. All primary spermatocytes contain 
each one larger and one smaller modified chromo- 
some. Further, during the histogenesis of the 
sperm the cuff of the spermatid is produced from 
nuclear sap, not from the cytoplasm, and since this 
cuff substance is thrown away with the abstricted 
cytoplasm the spermatid loses the greater amount 
of its nuclear sap. Therefore, this nuclear sap 
substance can not have the same value in inherit- 
ance as the other substances of the nucleus. 
To be published in full in the Journal of the 
Academy of Natural Sciences of Philadelphia, 
Centenary Volume. 
The X-element in Guwinea-chicken Hybrids: 
MicHaEL F’. GUYER, University of Wisconsin. 
The hybrids in question, all male, were the off- 
spring of a black langshan cock and a common 
guinea hen. The X-element of the chicken is very 
large, of stout build and typically of different 
shape from that of the guinea. While each usu- 
ally appears as a curved body, the X-element of 
the chicken is U- or bean-shaped with both ends 
of the same size, while that of the guinea is more 
comma- or pistol-shaped, with one end noticeably 
narrower than the other. The X-element of the 
hybrid was found to be invariably of the maternal 
(guinea) species type. In this fact may lie a 
simple explanation of why these hybrids were all 
male. For in all known cases it is the spermato- 
zoon without the large X-element which unites 
with the egg in the production of the new male, 
and since such a spermatozoon is much smaller 
than one of the other type, this mere difference in 
size may be the factor determining which shall 
fertilize the egg. Hybrids are obtained with diffi- 
culty even under the most favorable conditions and 
we may reasonably suppose that the egg-plasm is 
more or less resistant or antagonistic to the en- 
trance of a foreign sperm. If such is the case it 
would seem not improbable that the smaller type 
of spermatozoon with its diminished quantity of 
incompatible substance and its lessened surface 
against which resistance could operate, would 
penetrate more readily than the other, with the 
consequent production of a male. 
To appear in full in Journal of Morphology. 
SCIENCE 
[N.S. Vou. XXXV. No. 899 
Hight Factors that Show Sex-linked Inheritance 
in Drosophila: T. H. Morcan, Columbia Uni- 
versity. 
Hight factors that show sex-linked 
ance have appeared in cultures of the fruit 
fly, Drosophila. These factors without exception 
follow in their heredity the distribution of the 
sex-chromosomes with which they may be said 
to be linked. (1) The red eye of the wild fly is 
due to three factors—vermilion V, pink P and 
orange O. Of these V is not sex-linked, while P 
and O follow the sex-chromosomes. The red eye 
may be designated by V PO, the pink eye by vPO, 
the vermilion eye by VpO and the orange eye by 
vpO. Orange is present in all these cases, but 
since like P it is sex-linked (see below), it occurs 
in duplex in all females and in simplex in all 
males. The heredity of these eye colors has re- 
cently been published. (2) A new color has more 
recently appeared, due to the loss of the orange 
factor. The formula for this mutant seems to be 
VPo. The females have darker eyes than the 
males; thus giving a dimorphic race. The O factor 
proves to be sex-linked. It will now be possible, 
unless associative inheritance interferes, to produce 
a new series of reds, vermilions and pinks that 
lack orange; and an eye that lacks all color deter- 
miners, but contains the color producer C. (3) 
White-eyed mutants due to the loss of the color 
producer C have been described,? and these may 
carry the determiners for vermilion, pink or orange, 
ete. (4) The gray color of the wings of the wild 
fly is due to three factors—black B, yellow Y and 
brown Br. The formula for the wild fly is BYBr; 
for the black fly ByBr; for the yellow fly bYBr, 
and for the brown fly byBr. Of these three fac- 
tors black, B, is sex-limited; yellow, Y, is not; 
and Br has not yet dropped out, so that its dis- 
tribution is unknown. (5 and 6) Two wing mu- 
tants, described as rudimentary wings and mini- 
ature wings, both show sex-linked inheritance.* 
The miniature wing is due to the loss of a factor 
S; its formula is Ms. The rudimentary or 
‘short’? wing is Sm. When a miniature female is 
crossed with a short male, all the females (M/s Sm) 
have long wings; all the males (Ms..) have 
miniature wings. When the ‘‘short’’ female is 
erossed to the wild male all the females (Sm SM) 
have long wings, and the few males that ap- 
pear have short wings. The females are to the 
inherit- 
2 Jour. Exp. Zool., 1911. 
3 ScIENCE, 1910. 
4 ScrENCE, 1911. 
