268 Mr. GnirrirH on the Ambrosinia ciliata of Roxburgh. 
form. In the instance figured, the length to which they attained was immense. 
The matter squeezed out resembles exactly the process which originates from 
most globules of pollen, when acted on by water, and the very great length 
above noticed arose probably from the coalition of the processes of several 
granules occasioned by the pressure exerted. The opening € = cone 
appears to be of secondary importance; it is evident from the direction of 
the anthers, from the small size of the aperture, and from the relative dia- 
meters of the opening and globules of pollen, that it is not sufficient to allow 
of a free exit to the latter. The necessary free exit of the pollen is secured 
by the separation of the membrane from the inner margins of the thece, and 
at the time of fecundation the globules of pollen will be found uncovered. 
Although from this adaptation and the situation of the stigmata, a mere fall- 
ing out of the pollen globules would apparently be sufficient to ensure their 
application to the female organ, yet the agency of insects appears to be very 
generally resorted to as an additional insurance of the completion of this 
important function. The lower portion of the cavity of the spatha is during 
impregnation found to contain many small flies, which do not appear to be 
able to effect their escape after having done their duty, and are after impreg- 
nation found dead within the tube. 
At the earliest period at which I have examined the ovula, I have found 
them to be oblong bodies, projecting from the surface of the placenta, with 
Which in structure they have a great similitude. A little below their points 
there is a slight constriction, the part above this being papilliform and much 
less grumous than that below it. Ata somewhat later period, the base of the 
papilliform body, which is the rudiment of the nucleus, is surrounded by an 
annulus, a growth from that part of the ovulum situated below the constric- 
tion. This annulus is the rudiment of the integument of the ovulum ; it soon 
increases and forms a sort of cup, beyond the edges of which the nucleus pro- 
jects considerably. As the development proceeds the ovula become ovate- 
oblong, narrowed towards their bases and points, which are directed upwards. 
The nucleus soon becomes entirely inclosed in the cup, the mouth of which is 
then considerably narrowed : it is solid, papillose at its apex, which corre- 
sponds to the opening of the integument ; its tissue appenrs-to: be: more dense 
towards its base than at any other part. No change of any importance 
