ioo Campbell.* — Shidies on some Javanese Anthocerotaceae. II. 
Affinities of the Anthocerotaceae. 
Notothylas is without doubt the simplest and probably the most 
primitive of the Anthocerotaceae. Of the other genera Anthoceros closely 
resembles Notothylas in the general character of the thallus and sexual 
organs. Megaceros is to some extent intermediate between Anthoceros 
and Dendroceros , resembling the former in the general structure of the 
thallus, but having the solitary antheridium characteristic of Dendroceros. 
Whether the single antheridium is a more primitive character than the 
group of antheridia found in Notothylas and most species of Anthoceros 
it is impossible to determine. The question is also open as to whether 
the type of thallus in Notothylas and Dendroceros is the more primitive. 
A comparison might be made with the type of thallus found in 
Pallavicinia and Anenra among the Jungermanniaceae. In regard to 
the sporophyte, Notothylas , both in the smaller size and in the relatively 
larger amount of sporogenous tissue, is clearly the lowest member of 
the family. Of the other genera, Megaceros most nearly resembles 
Notothylas in the extent of the sporogenous tissue (Text-Fig. 2, B), but 
the columella and outer sterile tissue are very much better developed, 
and the sporogonium may reach a very large size, rivalling the largest 
species of Anthoceros , which, on the whole, it perhaps most nearly 
resembles, although the spiral elaters and absence of stomata are more 
like Dendroceros. In Dendroceros and the smaller species of Anthoceros , 
e.g. A. laevis y the sporogenous tissue is reduced to a single layer except 
at the summit, where in Dendroceros (Text-Fig. i, C) there may be a 
considerable increase in the amount of fertile tissue. The larger species 
of Anthoceros , with their highly developed assimilative tissue and perfect 
stomata, may probably be considered as the highest existing form of 
this peculiar form of sporophyte. 
The next question to be considered is the relation of the Antho- 
cerotaceae to other forms. The peculiar solitary chromatophore 
characteristic of most of these is so closely similar to that of many 
green Algae that it is probable it is an inheritance from some algal ancestor. 
This peculiarity has been supposed to be universal among the Antho- 
cerotaceae, but it has been recently shown that in the group of the 
genus Anthoceros , which the writer has proposed to separate as a special 
genus, Megaceros , there are normally several chromatophores in the inner 
cells of the thallus, and that these chromatophores are usually destitute 
of a pyrenoid and in all respects closely resemble the normal chromato- 
phores of the higher plants. 
Leitgeb has assumed a remote- relationship of Notothylas with the 
Jungermanniales, and believed that he had found sporogonia of the 
former in which the sporogenous tissue arose from the endothecial tissue. 
