474 Campbell. — Studies o?i some Javanese Anthocerotaceae. I. 
in the thallus of either species, but there are numerous large cells filled 
apparently with a mucilaginous substance which stains very strongly. 
The Sexual Organs. 
Both of the species of Megaceros under consideration are monoecious. 
Stephani (loc. cit.) states that in no cases did he find in M. Stahlii antheridia 
and archegonia upon the same branch, and thinks it may be dioecious. 
In both M. Tjibodensis and M. Salakensis the two sorts of organs are 
found upon the same branch, but, unlike most species of Anthoceros , the 
archegonia are developed first, and one may find fresh antheridia upon the 
younger parts of branches which bear advanced sporogonia. It may be 
that owing to this marked proterogeny Stephani failed to find antheridia 
and archegonia together. 
The Antheridium. 
The antheridia, as has already been noted in M. Vincentianus (?) 
(Leitgeb, loc. cit., p. 17) and M. Stahlii (Stephani, loc. cit.), occur singly, 
and in this respect resemble those of Dendroccros. As we have already 
stated, however, there is one species of typical Anthoceros , A. Pearsoni , in 
which solitary antheridia also occur, and this fact, together with the frequent 
doubling of the chromatophores in the inner cells, suggests an approach to 
Megaceros. 
The study of the development of the antheridium is attended with 
some difficulty owing to the mucilage developed about it in the chamber 
where it is formed. This mucilage evidently interferes with the penetration 
of fixing agents, and much of the material that was examined was found to 
have the younger antheridia so shrunken as to be quite useless for study. 
This was specially the case with specimens treated with 1 per cent, chromic 
acid, which otherwise proved the best fixing agent. Specimens fixed with 
acetic alcohol (alcohol, 90 per cent. ; acetic acid, 10 per cent.) gave much 
better results, although for the study of the archegonia and embryo the 
chromic acid yielded much better preparations. 
The early stages of the antheridium closely resemble those of 
Anthoceros Pearsoni (see Campbell, Mosses and Ferns, 2nd Edition, 
Fig. 57). The superficial cell from which the antheridium arises, as in all 
other Anthocerotaceae that have been studied, divides by a periclinal wall 
into an outer and inner cell, the latter in Megaceros , as in Dendroceros and 
Anthoceros Pearsoni , becoming at once the single antheridium. In the 
other species of Anthoceros and in Notothylas the inner cell divides by 
longitudinal walls into (usually) four cells, each of which develops into an 
antheridium. Before any divisions take place in the young antheridium, 
there begins to develop the cavity or chamber in which the antheridium 
