ation of some maturity. In the slime-mould the assumption of
walls is indeed delayed. Walls at length appear and when they do come
they are like those of the lily; they are cellulose. The myxomycetes may
be regarded as a section of the organic world in which the forces of
heredity are at a maximum whatever those forces may be. Slime-moulds
have in smallest degree responded to the stimulus of environment. They
have, it is true, escaped the sea, the fresh waters in part, and become
adapted to habitation on dry land, but nothing more. It is instructive
to reflect that even in her most highly differentiated forms the channel
which Nature elects for the transmissal of all that heredity may bestow,
is naught else than a minute mass of naked protoplasm. Nature reverts,
we say, to her most ancient and simple phases, and heredity is still
consonant with apparent simplicity; apparent we say, for as becomes
increasingly evident, nothing that lives is simple!

The fact is the Myxomycetes constitute an exceedingly well-defined
group, and the question of relationship in any direction need not much
perplex the student. Least of all is the question to be settled by
anybody's dictum, which is apt to be positive inversely in proportion to
the speaker's acquaintance with the subject. No one test can be applied
as a universal touchstone to separate plants from animals. Such is
simply _petitio principii_. Nor is there any advantage at present
apparent in attempts to associate slime-moulds with other presumably
related groups. Saville Kent's effort to join them with the sponges was
not happy, and Dr. Zopf's association of the slime-moulds and monads
appears forced, at best; for when it comes to the consideration of the
former, their systematic and even morphological treatment, he is
compelled to deal with them by themselves under headings such as
"Eumycetozoen," "Hoehere Pilzthiere," etc. One rather commends the
discreetness of DeBary, whose painstaking investigations first called
attention to the uncertain position of the group. After reviewing the
results of all his labors DeBary does not quite relegate the
slime-moulds to the zoologist for further consideration, but simply
says:[12] "From naked amoeba, with which the Mycetozoa (=Myxomycetes)
are connected in ascending line, the zoologists with reason derive the
copiously and highly developed section of the shell-forming
Rhizopoda.... And since there are sufficient grounds for placing the