PROGRESS IN PROTOZOOLOGY

16 B. M. HONIGBERG
semblage or establish new ones for these genera. Thus there still remains
a group of former rhizomastigotes which will have to be considered for
some time as species incertae sedis.
It has been pointed out by Vickerman that one of the problems
in placing "lower" zooflagellates in an order is how minimal a definition
of the order is acceptable. A good example of this problem quoted by
him is the assignment by Hollande (1980) of Perkinsiella, the endobiont
of the parasitic amebae Paramoeba and Janickina to KINETO-
PLASTIDA. Perkinsiella has, indeed, a single mitochondrion rich in
DNA fibrils which, however, are isotropic in their arrangement. On the
basis of the available data, Vickerman concluded: "In the absence
of any sign of a flagellar apparatus or pellicular microtubules and of
information on nuclear division, the writer would hesitate to assign this
organism to KINETOPLASTIDA, though it is possible that adaptation
of Perkinsiella to existence as an organelle of its amoeba host may have
robbed it of most of its kinetoplastid characteristics." Although Hollande
(1980) claimed that: "... les microtubules situés à la périphérie
du cinétoplaste pourraient être homologues de ceux qui, dans une cellule
de Cryptobia sont sous-jacents à la pellicule;..." one would tend to
concur with Vickerman that the evidence for the presence of subpellicular
microtubules is not compelling. In general, although an admirer
of Prof. Hollande's cytologic researches, I cannot help but feel
that assignments of flagellates or any other protozoa to given taxa
ought to be based on stronger evidence than that provided by him for
Perkinsiella.
It is evident from the foregoing discussion that although much is
known about both the pigmented and nonpigmented flagellate groups,
which constitute the basic assemblages of the greatest importance to
evolution of eukaryotes, there remain many important problems still to
be solved. Clearly the solution of some of these problems will depend
upon mutual understanding and effective collaboration among protozoologists,
phycologists, and mycologists.
Appendix to MASTIGOPHORA
Prof. W. Michajlow presented his views on the taxonomy and
taxonomic criteria that ought to be employed for the group of parasitic
euglenoids "Euglenida parasitica," which he has been studying for many
years. Since we are concerned in the present discussion primarily with
higher taxa, we cannot consider details of taxa below suborders. It suffices
to say that in classifying the parasitic euglenids, Michajlow wishes
to employ the following criteria: 1. structure of parasitic and free-living
forms (present in the life cycle); 2. details of the developmental cycles;
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