QUARTERLY CHRONICLE OF MICROSCOPICAL 
SCIENCE. 
BOTANY. 
Sexual Reproduction of Thallophytes. 
I 
Tue theory of descent has given—as it has done to 
every other branch of Biology—an entirely new interest to 
the study of the lower Cryptogams. They represent forms 
which if not actually identical with those possessed by the 
remote ancestors of the more complex plants have probably 
not been very distantly removed from these ancestral forms 
by subsequent modification. 
It is natural, therefore, to seek amongst the non-vascular 
cryptogams for indications of phylogenetic relationship. But 
any examination for such a purpose must of course be un- 
satisfactory which is not based on a sufficient knowledge of 
the life-histories of the different types. Without this it 
is impossible to compare them one with another at stages 
when such a comparison is really significant. 
Unfortunately from the necessity which is constantly im- 
posed upon the systematist of classifying organisms of all kinds 
without being able to fulfil such a condition, the most erro- 
neous juxtapositions are constantly made, and although an 
immense body of accurate observations has been accumulated 
about different types of the lower cryptogams, it is only lately 
that anything like a real cohesion has been visible amongst 
the accumulated facts. In the fourth edition of his ‘ Lehrbuch 
der Botanik,’ published towards the end of last year, Sachs 
has proposed and adopted a classification of the non-vascular 
cryptogams which, while widely differing from any which 
had been previously suggested, for the first time affords 
something like an intelligible view of their morphological 
evolution. 
if: 
The division of the vegetable kingdom into the two 
regions of THALLOPHYTA and CorMoPHYTA was proposed by 
Endlicher in 1836. The groups are still valid, though it is 
by no means easy to frame characters which will satisfactorily 
limit them. Except perhaps the absence or presence of the 
