296 Lang.—Development of Cycadean Sporangia. 
The spermatozoid is of large size and possesses cilia attached 
to a blepharoplast which forms a spiral of five turns. 
5. By the absorption of the intervening tissue of the nucellus 
a free passage is formed between the pollen-chamber and the 
prothallus. The spermatozoids, on their escape from the 
pollen-tube, which only bends down for a short distance, 
probably reach the archegonium by their independent motility. 
6. The embryos, which are formed singly at the lower ends 
of the archegonia as in Cycas , possess long suspensors and 
come to occupy a common cavity formed by absorption of 
the tissue of the prothallus; ultimately one embryo becomes 
dominant in each seed. 
7. The embryo frees itself from the prothallus before the 
cotyledons are formed; these become in turn intimately 
attached to the prothallus. 
The mature Microsporangium of Stangeria. 
A Correction. 
In the first number of these studies too close a comparison 
was drawn between the microsporangia of Stangeria and the 
sporangia of Angiopteris. Since the resemblance between 
the microsporangium and ovule may be of importance in 
discussing the results obtained from the study of Stangeria , 
this opportunity may be taken of correcting the erroneous 
impression conveyed in my earlier paper; at the same time 
some additional facts ascertained regarding the microspor¬ 
angium may be stated. 
The error referred to does not concern any of the points 
illustrated in the figures of my former paper, but is contained 
in the reference to the sporangium of Angiopteris on p. 432. 
The view there expressed was that bands of thicker-walled 
epidermal cells on either side the line of dehiscence in the 
microsporangium of Stangeria might be regarded as cor¬ 
responding to the distinct lateral bands of indurated cells 
in a corresponding position in Angiopteris. Further observa- 
