39 2 Mottier . — Contribtitions to the 
sporogonia. By gathering specimens earlier in the season one 
is sure to find both sex-organs and sporogonia in different 
stages of development on the same semicircular or circular 
expansion of thallus. 
According to the views of Leitgeb 1 and Goebel 2 , Notothy- 
las is regarded as representing a transition from Anthoceros to 
the Jungermannieae. This view is based mainly upon the 
structure of the sporogonium, particularly the limited growth 
of its capsule and the nature and origin of the columella. 
Hofmeister has also made careful and extended observa- 
tions upon the Hepaticae, but unfortunately his works are 
not accessible. 
Goebel 2 states that the capsule of Notothylas either has not 
a columella, or has one which is only a secondary differentia- 
tion inside the spore-chamber. In another place 3 the same 
author says that there are species of Notothylas which possess 
a columella similar to that of Anthoceros , but of its origin 
nothing is known ; that, in fact, it is uncertain whether this 
arises, as in Anthoceros , with the archesporium though inde- 
pendently of it, or whether it is a product of a gradual differ- 
entiation in the spore-chamber. 
For a detailed knowledge of these Liver- worts we are 
indebted to Leitgeb, who, in his admirable work Unter- 
suchungen liber die Lebermoose , has published the results of 
careful and extensive investigations. 
Four species of Notothylas were examined by this author, 
N. fer tills, N. valvata , N. Breutellii , and N. melanospora. 
Leitgeb 4 states that in some species of Notothylas, there 
occur capsules, which, in regard to the size (Machtigkeit) of 
the columella and the difference of its cells from the other 
sterile cells of the spore-chamber, do not differ from the 
capsules of Anthoceros ; and it may be possible, though not 
probable, that these capsules, in respect to the origin of their 
1 Untersuchungen iiber die Lebermoose, Heft V, 1879. 
2 Outlines of Special Morphology, p. 158, English translation (1887'. 
3 Schenk in Handbuch der Botanik, Band II, p. 357 (1882). 
4 Loc. cit., Heft V, p. 7. 
