Wo.35| 2HE. 2GG OF ALLOLOLZOPAHORA FOETIDA. 479 
spindle differs constitutionally from the central, as it exerts no 
influence on the sperm. In one preparation a spermatozoon 
has entered near this aster and is in process of passing it, on 
its way towards the central aster. 
After the complete separation of the first polar body the 
head of the sperm is found to be contracted into a relatively 
short, thick rod distinctly separated from its aster (Fig. 3), and 
occupying a position in relation to it, varying from the radial to 
tangential. This separation seems to be caused by the thicken- 
ing and consequent shortening of the head, as in earlier stages 
the head and aster are almost in contact and the former is 
relatively longer and more thread-like. During the process of 
constriction of the first polar body (seen in several specimens), 
the successive stages of contraction of the head of the sperm 
can be followed. 
The chromosomes of the first maturation spindle are 
extremely pronounced ; their shapes and number can therefore 
be accurately determined. The individual chromosomes of the 
spindle shown in Fig. 1 have been selected from three speci- 
mens, in order to combine in one spindle some of the various 
forms seen. 
There are eleven chromosomes in the first maturation 
spindle (Fig. 4), eleven in the first polar body, eleven in the 
second maturation spindle (Fig. 5), 
eleven in the second polar body, 
and eleven in the egg after the se- 
cond polar body is constricted off. 
The second maturation spindle, 
when it has reached the meta- F!6- 4. Polar view of first matu- 
ration spindle. 
Fic. 5. Polar view of second 
maturation spindle. 
phase, is quite as large as the first 
spindle ; therefore, as Boveri (2) 
suggests, its achromatic substance 
must be replaced from the cytoplasm. The position of the 
spindle is radial, or slightly oblique, and the two asters are as 
pronounced as those of the first spindle. 
Polar Bodies.— Two are constricted off from the egg and a 
third is formed by a division of the first. The three have 
about the same degree of transparency and the same general 
