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 rhizopods outside the vegetable and in the animal kingdom, and this is undoubtedly the true position for the amoebae, which are their earlier and simpler forms, the Mycetozoa, which _may_ be directly derived from the same stem, are at least brought very near to the domain of zoology." Notwithstanding all the controversy in regard to the matter, the study of the slime-moulds still rests chiefly with the botanists. A simple phylogenetic scheme for thallophytes is offered in the Strasburger text as follows:-- THALLOPHYTA 1. SCHIZOPHYTA BACTERIA CYANOPHYCEAE 2. FLAGELLATA { MYXOMYCETES { PERIDINEAE _a_ { CONJUGATAE { HETEROCONTAE { CHLOROPHYCEAE _b_ { CHARACEAE 3. RHODOPHYCEAE 4. FUNGI