TRANSACTIONS OF SECTION K. 871 



of species of Lycopodiiim. I hope to investigate the fungus more closely iu a 

 living condition during the next period of vegetation. The fungus filaments 

 can be seen passing from the prothallium to the outside medium by way of the 

 I'oot-hairs. 



The antheridia, as has been already stated, occur in numbers on a ridge 

 running lengthwise on the upper surface of the prothallium. The young antheridia 

 originate behind the growing point from a single superficial cell. This divides 

 transversely the outer half, giving rise to the outer antheridial wall and the inner 

 half by repeated simultaneous divisions to a large number of spermatocytes. The 

 fully developed antheridium is largely embedded in the antheridial ridge, and 

 projects only slightly above its surface. The formation of the spermatozoids has 

 not yet been carefully studied, but seems to resemble closely that described in the 

 Marattiaceaj and Equisetacese. 



The spermatozoids are unusually large in size, but otherwise resemble the 

 ordinary fern type, and consequently differ from the biciliate, moss-like spermato- 

 zoids of the Lycopodiales. 



The archegonia are confined to the sloping sides of the upper surface of the 

 prothallium. Unlike the antheridia, young archegonia, although most abimdant 

 near the growing point, may be formed on almost any part of the archegonia- 

 bearing surface. The archegonium mother cell is superficial, and is distinguished 

 from its neighbours by a larger nucleus and a more- abundant protoplasm. It first 

 divides transversely into a shallow outer cell and a deeper inner cell. The inner 

 cell divides again, and as a result the young archegonium consists of three cells. 

 The most external of these, by subsequent divisions, gives rise to the neck of the 

 archegonium. The internal cell is the basal cell. It also divides into a plate of 

 cells sometimes composed of two layers and distinguished by their richly proto- 

 plasmic contents. The middle cell of the young archegonium series gives rise by 

 division to the neck canal cell and the ventral cell. The former becomes binu- 

 cleate, but never divides into two cells. The latter, just before the maturation of 

 the archegonium, divides into the egg-cell and the ventral canal cell. The ventral 

 canal cell is broad, like that of the Marattiacese. 



In the ripe archegonium the nuclei of the cells of the upper storeys of the arche- 

 gonium neck become chromatolysed. I do not know yet whether this feature is 

 peculiar to Botrychium. 



The fully developed archegonium is sunk into the prothallium, and only the 

 neck projects above its surface. The cervical cells are in four rows as in the other 

 Pteridophyta, and the terminal ones spring apart when the egg is ripe. 



Spermatozoids are frequently found in contact with the egg. After fertilisation 

 the egg grows to many times its original size, and the reduced protoplasm contains 

 a large hydroplastid. 



The first division of the oospoi-e is across the long axis of the archegonium. 

 The next division is parallel with the long axis of the prothallium, and at right 

 angles to the first. The third cross wall is in the transverse direction of the pro- 

 thallium, and at right angles to the other two. I have been unable to follow 

 satisfactorily the subsequent divisions. 



The organs appear very late, and only after the embryo has attained a large 

 size. The root is the first of them to emerge, and the proliferation of cells, indi- 

 cating its place of origin, is long unmarked by the presence of an apical cell. The 

 cotyledon, stem apex, and foot appear nearly simultaneously. 



The root and cotj'ledon originate from the upper part of the embryonic mass ; 

 the foot and stem apex from its lower cells. 



The apex of the root in many cases is in the same straight line with the canal 

 of the archegonium neck. 



It seems hardly possible to derive the organs from definite octants of the 

 embryo. 



The gi-owth of the root ruptures the calyptra, and its exit is followed somewhat 

 later by that of the cotyledon. The latter is not a bilaterally symmetrical 

 structure, as in most ferns, but is of the same palmate type as is found in the 



