No. 3.] 7HE EGG OF ALLOLOBOPHORA FOETIDA. AT] 
formed while one or more spermatozoa are penetrating the 
periphery of the egg. 
The area of the cytoplasm through which the spermatozoon 
enters shows a cone-shaped structure, — Fig. 1. In this case 
three spermatozoa are entering about the same moment and at 
various points. The slight projection of the cone beyond the 
periphery would suggest that it is of the nature of a “cone of 
attraction’’; and in some cases the projection is much more 
marked than is represented in the figure. At present, how- 
ever, I do not feel justified in giving a decision on this point, 
as I have no preparations showing a cytoplasmic extrusion as the 
sperm comes in contact with the egg, and I have one specimen 
which suggests that the sperm must enter a definite distance 
before the cone appears. Fick (5) shows a similar cone-shaped 
structure in Axolotl, which is undoubtedly of the same nature 
as that of Allolobophora foetida, although the former appears 
later, differs somewhat in relative shape and according to Fick, 
originates by an invagination. The cone persists until the first 
polar body is in process of constriction. After that stage of 
development has been reached the cone has disappeared, and 
in most cases the sperm aster is seen at the point previously 
occupied by the apex of the cone. In all cases it is at that 
point of the spermatozoon immediately posterior to the head, 
— the point which has been designated as the middle piece. 
In a few preparations, where a tardy spermatozoon is 
relatively near the periphery of the egg, when the first polar 
body is being constricted off, the aster is forming near the base 
of the cone while traces of the cone structure still persist. 
Thus we see that the aster appears immediately on the 
formation of the first polar body, without regard to the 
exact location of the middle piece in the egg. In two pre- 
parations, where the head of the sperm is penetrating the 
egg, at the time the first polar body is being constricted 
off, there is no aster present, and thus we have negative 
evidence that the middle piece is necessary to the formation 
of the aster. This seems to be a confirmation of the results 
obtained by Calkins (4) in his study of the spermatogenesis of 
Lumbricus. 
