124 
Alice M. Boring 
biirdly possible to tbiuk tbat tlie sbortness of one of tbe loug cbro- 
mosonies bere is due to a diöerence in tbe degree of contraction. 
Tbe small cbromosome was fouud also in bastard eggs, as well 
as in tbe pure hivalens and univalens eggs. In two feniales one 
biralejis and one univaletis, a number of bastard eggs wer e scattered 
among tbose fertilized by tbe spermatozoa of tbeir own variety. 
In anotber univalem worm tbere was one bastard, and in several 
niore worms, spermatozoa of botb varieties were found in tbe uteri. 
Tbis sbaws tbat it is not an unusual tbing for one female Ascai'is 
to be fertilized by males of botb varieties. Tbe spermatozoa of tbe 
two varieties can be easily distinguisbed as Meyek (’95, Figs. 26 a 
and b) bas sbown, because tbe volume of tbe deep-staining cbromatic 
part in univalens is mucb less tban half as great as in hiralem. In 
accordance witb tbis, Fürst (’97) bas pointed out tbat tbe cbromo- 
somes of tbe two varieties can be distinguisbed in tbe first cleavage 
Stage not only by tbe difference in number, but also by a very 
marked difference in tbe volume. Tbis makes it very easy to reco- 
gnize tbe bastard eggs, as tbey must always bave two large cbromo- 
somes from tbe bivnlens parent, and one smaller one from tbe uni- 
calens parent. Zo.ja’s figures ('95) sbow tbis clearly. Tbe small 
cbromosome also is of larger diameter in hivalens tban in uni- 
rnlens. Compare figures 2 and 3. 
As one can ascertain whether tbe maternal parent is bivalens 
or univalens by study ing tbe polar bodies and tbe pure eggs among 
wbicb tbe bastards are found and wbetber tbe small cbromosome is 
from bivalens or univalens by studying its size , tbe bastards may 
furuisb a way of finding out wbetber tbe small cbromosome comes 
exclusively from tbe egg or from tbe Spermatozoon, or from botb. 
Herla figures one bastard [bivalens Q X univalens (5’) witb a small 
cbromosome h ing near tbe maternal group, one of wbicb is so sbort 
tbat tbe small cbromosome is apparently a piece of it. I bave found 
several such bastards but never witb tbe small cbromosome present. 
Among tbe bastards [univalens Q X bivalens (f), live eggs witb a 
small cbromosome were found, three where it is of large diameter 
and lies near tbe paternal group, (Figs. 5), and two where it is of 
intermediate diameter, and lies near tbe maternal cbromosome (Figs. 6). 
Tbere is a bare possibility tbat in these two latter cases, it is large 
euougb to belong to tbe bivalens group. If so, it bas shifted its 
Position considerably since tbe dissolving of tbe walls of tbe pronuclei 
and tbe condensing of tbe spireme to form tbe chromosomes. So 
