244 THE ESSEX NATURALIST.
nately the specific determination of the specimens has not been
possible as a rule, but Isotoma minor and Onychiurus armatus have
been noted and also a species of Sminthurides.
In concluding this resume of my observations on the micro-
scopic life of the leaf-carpet, one or two points deserve a little
attention. In the first place it will be evident that the deter-
mination of the species of organisms present has been very unequal
in the different groups. The fact is, of course, that no one person
can hope to be able correctly to identify specimens of so many
types of plants and animals. The work, to be properly carried
out, evidently requires the collaboration of a number of specialists,
each with a very thorough knowledge of the species already des-
cribed in his own particular group. Some day perhaps a piece
of team work will be begun with a view of obtaining as complete
a list as possible of all the micro-organisms of the leaf-carpet and
evidence of their exact systematic rank. I think it is quite
possible that, upon more critical examination, some of the forms
will be found not to be typical of the species under which they
have been recorded, but good varieties or even distinct species
peculiar to, or at least characteristic of, the leaf-carpet.
Another point is as to the differences which may be expected
to be found in the microscopic fauna and flora of different types
of leaf-carpet. The most marked outward difference in this
respect is evidently between the leaf-carpet of pine woods and
that of the deciduous woods. Nearly the whole of my samples
have been of the latter type, but two or three have been from the
former. Except that from the pine woods the number of forms
seen in each case was much less than normally from deciduous
woods, there were no marked differences in the species noted. As
already mentioned, however, the only actively moving Diatoms
seen during the whole investigation came from a pine wood leaf-
carpet, but whether this is of any significance is not known. The
possible differences between sub-divisions of the deciduous
woods, e.g., Beech, Oak, Birch, Mixed Beech and Oak, etc., is a
subject, no doubt, worthy of consideration, but so far as I can
judge from my results there appears to be no outstanding differ-
ence.
Yet a third and last point, that is concerning the role played