476 
J. JBKONTE GATENBY. 
PI. 26, fig. 13, the granule (6r.) it really an acrosoine 
is not orientated towards the front of the nest, but 
in the greater number of cases in all abnormal stages 
the acrosome keeps towards the front end of the cell. 
What cell element causes this sensible orientation ? Is it 
centrosome or nucleus ? Tlmt it is not the former might 
be concluded from the history of the normal sperm where 
the centrosome is at the back of the nucleus, and in a 
position which one might be justified in presuming, unable 
to affect the acrosome. The facts of the influence of the 
acroblasts upon the nucleus, and of their very apparent 
inter-relationship leads me to believe that the nucleus might 
have something to do with this orientation of the acrosome 
in the direction of the head end, though more probably the 
whole question should be considered in relation with the 
growth of all the elongating spermatozoa in one direction, 
which is a fact which has already attracted attention. In 
the worm (Lumbricus) the spermatozoa grow outwards in 
a beautifully regular manner to form a ball, and here there 
is no sperm nest-wall. In several abnormal bundles of moth 
spermatozoa I have found that this growing outwards in 
a common direction by all spermatozoa is not completely 
perfect. In the testis the bundles of normal spermatozoa are 
cut across in all directions showing that this growing out 
of all tails in one way is a matter concerning individual 
bundles. I have not examined the part played by the sertoli 
or nurse-cells with sufficient completeness to give even a 
tentative statement, but I believe that this cell may be 
intimately concerned in the orientation of sperm and sperm 
elements. 
The partial isolation of the acrosome from the nucleus in 
abnormal stages shows that the element which causes the 
adherence of one body upon the other is here lacking or 
inefficient. Just as the nucleus is often unable to adhere 
to the head centrosome, or vice versa, so the acrosome 
sometimes may lie quite near, quite completely formed, but 
lacking the power to become adherent. The manner by 
