268 Mr. Griffith on the Ainbrosinia 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 in the 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 thecse, 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. At a 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 appears to be more dense 

 towards its base than at any other part. No change of any importance 



