elx Proceedings of the Astatic Soctety of Bengal. [N.S., XV, 
that reduction or differentiation does not affect all the organs 
equally. 
Now I come to the two genera which are usually placed 
in the family Targionaceae. They differ considerably from each 
other. The study of the Indian species Cyathodium tuberosum 
by the writer has att n that the family is not so distinct from 
the so-called Ma i glases as has generally been supposed. 
The great interest of the study of Cyathodium lies in the fact 
that the genus is undoubtedly reduced and is accepted as such 
The most distinguishing character of this family is the ter- 
minal involucre situated at the apex of an ordinary vegetative 
shoot. We might say that the erect stalked receptacle of the 
Marchantia-type has become prostrate, or better still that the 
the present series vegetative growth has taken plac hind 
the sex organs with the result that the latter appear, not on 
an abbreviated receptacle, but at the en or less 
elongated vegetative shoot. The transitional form between the 
stalked terminal receptacle of the Exor motheca-ty pe and the 
y 
nap is of the same general structure as that of the two 
adjacent types. 
The series is so complete that there can be no doubt as to 
the forms being really related. The only question that can 
arise is as to the direction in which egy tage has proceeded, up- 
wards or downwards. It is here that duced genus Cya- 
thodium aflords us great help as meena did in a similar 
matter. The male receptacle in this genus under ordinary con- 
ditions is a simple cushion-like structure situated on one side 
of a vegetative shoot or in between two such shoots. In bet- 
ter developed plants under favourable a gre onesie the receptacle 
mes large and of a composite type comparable with that 
of Marchantia but sessile and therefore Be OM ing the more 
receptacle of Aitchisoniella but having more lobes. It show 
that the original form — which Cyathodium has arisen came 
from a higher type like Marchantia 
The Targionia-type “eh still firihes led to lower types by 
the gradual shifting of the sex-organs to the dorsal surface and 
the elimination of the involucre. so that ultimately the same 
type is reached which was arrived at in other cases by a differ- 
ent route described above. This is astrikingexample of conver- 
