933 



controverted point, and one on which we may have much hereafter to 

 say, we have endeavoured to render the author's words as exactly as 

 possible. 



" In the origin of such an organ the cellular layer [of the pro- 

 embryo] becomes thickened by the formation of new cells. By this 

 process a large, globular, intercellular space is formed, having a con- 

 tracted orifice at the exterior extremity. The latter is generally six- 

 sided, and is closely surrounded by green and usually quadrangular 

 cells. The larger and more remote cells contain but little chlorophyll. 

 From the margins of the cup-like orifice arise four rather large cells, 

 arranged in a circle, containing a transparent fluid and being without 

 nuclei : between these is a square intercellular space, which varies in 

 size : from each of them three more are developed, virtually one 

 above another; so that the square space becomes elongated into a 

 canal, which leads to the interior of the organ. The cells at the apex 

 are usually so closely approximate as to close the orifice. On ac- 

 count of the early origin of the canal the cavity seldom appears un- 

 covered. 



" These bodies, so different in structural characters, possess also a 

 different physiological function, although [by some observers] re- 

 garded as antheridia in a more advanced state of development. By 

 continual observation I have succeeded in discovering in them the 

 sexual apparatus of ferns, hitherto regarded as cryptogamic. In the 

 hollow oval bodies last described I recognize the female apparatus." 



The passage immediately following we do not exactly comprehend, 

 unless its meaning be to argue that the relative position of the male 

 and female organs points out the true office of both. The author de- 

 scribes the ovule, which he finds within the pistillidium and near its 

 base, as without envelopes, and as being a simple, naked nucleus, 

 divided into two parts ; the larger upper portion, or nuclear papilla, 

 projecting from the surface of the pro-embryo, and the lower smaller 

 portion, or cavity for the embryo-sac, buried in its substance. In the 

 first there is again to be distinguished— -first, the apical orifice or 

 opening of the nuclear papilla ; and, secondly, the continuation 

 thereof, or canal of the nuclear papilla, leading to the cavity from the 

 embryo-sac. The orifice is directed towards the base of the pro- 

 embryo. 



" Before the formation of the nuclear papilla, the embryo-sac arises 

 at the bottom of the cavity already described, in the form of a minute 

 transparent cell : this is seated on a small tubercle, which serves as a 

 point for its attachment. Even at this early period we may detect 



