cliv Proceedings of the Asiatic Society of Bengal. [NS., XV, 
from the simplest to the most complex, especially if only one 
or two characters are taken at a time. This is certainly the 
case with the sa agerecony! the Marchantiales. Sup- 
posing that a given se of this kind represents a natural 
group of plants we have 0 iuades further whether it is really 
an ascending as it is of course possible that the forms in 
found in nature or sometimes put in hypothetically to complete 
a series. The argument from such forms cuts both ways. If 
we possessed all the intermediate forms necessary to bridge 
the gulf between the Liverworts and the Pteridophytes for 
example (and we do not possess these) it would not necessarily 
prove that the Liverworts were the plants which gave rise to 
i Pteridophytes or some similar higher forms. The converse 
v have been the case. That it has been so, can. I think, be 
airs a clearly. 
Bearing Pshess considerations in mind let us see what con- 
nection can be traced between the Liverworts and the Algae. 
As has been stated above there is a big gap between the two 
and it has not been found possible to bridge it so far. sl tt 
forms among the Algae do show a certain amount of re: 
blance to the Liverworts but this is bade sitientsh ond very 
incomplete even when we consider a single character. Three 
algal forms have usually been mentioned in this connection, 
Coleochaete, Chara and Ectocarpus. It is not maintained that 
a 
_— the plants are widely different in other respects. 
oleochaete resembles the simplest genus of the Marchan- 
Ay Riceia, in having a small globular fruit—body resembling 
the capsule of the latter. It is well known, however, that the 
outer envelope in Coleochaete has an altogether different origin 
from that of the wall of the capsule of Riccia and belongs to a 
different —_— Then the structure of the thallus and of the 
sex organs in Coleochaete is ee different from the structure of 
even a simple at Campbell says, ‘‘ It is pretty gener- 
ally conceded that the origin of the whole archegoniate series 
is to be sought somewhere among the green Algae, and that 
on the whole pap emt is, perhaps, the form which i is nearest 
to the ec ineae.”’ A little later he says, “‘ At best, 
the connec (a honaeels any known Alga and the Muscineae is 
