444 SECOND PART. —MYCETOZOA. 



highly differentiated Acrasieae, on the other into forms which produce plasmodia. 

 Plasmodiophora, which will be further noticed below, is perhaps one of the simplest 

 representatives of the latter kind, though this must remain uncertain for reasons 

 which will be stated. In the group of the Myxomycetes the type becomes highly 

 differentiated. 



From these naked Amoebae with which the Mycetozoa are connected in the 

 ascending line, the zoologists with reason derive the copiously and highly developed 

 section of the shell-forming 'Rhizopods,' as they are understood by Fr. E. Schulze and 

 Biitschli, though the course of their ontogenetic development is still imperfectly 

 known. 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 simpler and earlier forms, the Mycetozoa which may be 

 directly derived from the same stem are at least brought very near to the domain of 

 zoology. It has been already pointed out that the Mycetozoa show only a slight 

 agreement, either in the general course of their development or in the characteristic 

 features of its separate stages, with organisms which are of undoubted vegetable origin, 

 whether they be Fungi or plants other than Fungi ; the agreement, with the exception 

 of the few cases in which cellulose makes its appearance, is confined to phenomena 

 which are common to all organised bodies. It is exactly in the species, which like 

 Lycogala and Fuligo are most like the Fungi, that the agreement is of the smallest 

 possible amount, being confined to purely external marks such as those between birds 

 and winged insects. On these various grounds, which have been worked out at 

 different times with greater or less clearness according to the state of our knowledge, 

 I have since the year 1858 placed the Myxomycetes under the name of Mycetozoa 

 outside the limits of the vegetable kingdom, and I still consider this to be their true- 

 position. 



We may further enquire whether closer ties of relationship do not appear at 

 some point or other between the group of the Mycetozoa at their lower limits and 

 members of the vegetable kingdom. In the search for these and judging by known 

 facts, we find that the only forms which we can take into consideration are the 

 Chytridieae which have no mycelium, as Synchitrium.Olpidiopsis, Rozella andWoronina 

 (see sections L-LII). It has been already more or less distinctly stated that these forms 

 are nearly related to the Mycetozoa. They agree with the Myxomycetes, first in the 

 peculiar circumstance that the entire vegetative body is finally transformed into one 

 many-spored sporangium, secondly in the fact that their spores and the vegetative 

 body itself in the young state have the power of amoeboid movement for a longer or 

 shorter time. But these are phenomena which are common to them and many other 

 Thallophytes, with which no one ever has supposed or ever will suppose them to have 

 any near affinity, Botiydium for example or Porphyra ; it is plain also that they have 

 been appealed to from a wish to find some group of undoubtedly vegetable forms in 

 which the Myxomycetes could be included. Of the characteristic phenomena of 

 development in the Mycetozoa, the Chytridieae mentioned above show neither the 

 aggregation of the Acrasieae, nor. the formation of Plasmodia by coalescence of swarm- 

 cells. If the term plasmodium has in their case been used to describe bodies 

 originating in the growth of a single spore, this arose either from an erroneous idea 

 (Cornu), or it is a misuse of the word, for though Chytridium in its young state often 



