654 Camp hell . — The Structure and Affinities of 
The apex of the gametophyte is occupied by a row of similar marginal 
cells, no one of which can be certainly identified as a single apical cell 
(PI. XLVI, Fig. 12), although it is possible that the central cell of the marginal 
row may be a definite apical cell. In horizontal section the marginal cells 
are oblong, and narrower in front. A vertical section shows the usual 
form found in Fern prothalli, i.e. it appears semicircular with single basal 
segments extending the whole depth of the thallus (PI. XLVI, Fig. 13). 
The Antheridium. 
The antheridium in Macroglossum is very much like that of the other 
Marattiaceae in its development. Antheridia are produced abundantly 
both on the dorsal and ventral surfaces of the prothallus. As in all of the 
eusporangiate Ferns, the mother-cell first divides into an inner and an outer 
cell, the former by subsequent divisions giving rise to the mass of 
spermatocytes ; the outer one, by a series of intersecting walls, forming 
the cover. There is a more or less regular quadrant division of the inner 
cell (PI. XLVI, P'ig. 15), beyond which it is not possible to trace any 
regular sequence in the divisions of the sperm-cells. 
Surrounding the mass of sperm-cells there are later cut off from 
the adjacent tissue the characteristic narrow, mantle cells (Figs. 18, 19 y m.). 
In the cover cells, as in other Marattiaceae 1 and in Ophioglossum , 
a series of intersecting walls is formed, the last division cutting out a small 
triangular opercular cell, which is destroyed at the time of dehiscence 
(Figs. 20, 21). 
The number of spermatocytes is very large in Macroglossum , probably 
exceeding that of any other of the Marattiaceae. In the larger antheridia 
as many as a hundred spermatocytes may be seen in a single section. 
The spermatozoids, however, are smaller than is usual in the Marattiaceae. 
The development of the spermatozoid is entirely like those of other 
Marattiaceae. The nucleus of the spermatocyte has no nucleolus and 
soon begins to assume the characteristic curved form (PL XLVI, Fig. 22), 
finally becoming much elongated. The blepharoplast, which at first is 
globular, very soon becomes elongated and forms a slender coiled body 
lying along the curve of the nucleus. From the blepharoplast the cilia are 
developed, but the details were not followed, as there seemed to be no 
peculiar features present. The free spermatozoids were not seen. 
On comparing the spermatozoids with those of Angiopteris (PI. XLVI, 
Fig. 24) they are found to be slightly smaller and the nucleus rather less 
elongated. In the latter respect Macroglossum perhaps more nearly 
resembles Danaea than it does Angiopteris . 
1 See Campbell, loc. cit. 
