xxviii PREFACE. 
vided into three parts, the uppermost which is gene- 
rally conical and more transparent is the nucleus, the 
first developed portion, that which is contained between 
the two lines forms afterwards the second integument, 
the remainder of the base forming the outer coat or 
testa. But while these boundaries are being marked 
out, secondary changes may or may not be going on 
when the former is the case, it consists of a sort of in- 
version in direction of the ovule, by which the apex 
of the nucleus is brought towards the point 
of existence of the funicle from the placenta. The next 
step is the production upwards of the ring marked out 
between the two lines of construction, or one line 
only is formed by the production of the part imme- 
diately contiguous to the line, a ring is thus formed 
which embraces the base of the nucleus, shortly after- 
wards that which becomes the outer coat is similarly 
extended round the base of the second coat. 
Both these continue to elongate, but the inner coat 
maintains for some time the ascendency and at length 
entirely encloses the nucleus, beyond which it is gene- 
rally continued into 2 neck variable in length, always 
open and generally somewhat dilated at its extremity. 
The outer coat by its gradual extension at length 
EF. ewise entirely encloses the nucleus, and the body of 
the inner integument, it frequently encloses the whole 
of this, while often before fecundation and for some 
time after the neck of this last projects to a consider- 
able distance.* 
* No one bas enquired, how the base of the ovula is extended 
downwards, or how the base of the second coat extends down- 
wards into the substance of the outer, does it or does it not? 
ee On ee D NOS, eT eee T 
