and have been placed in the special genus Holospora Haffkine. The spores appear to resemble
the endospores found in the genus Bacillus Cohn.
Because the majority of these intracellular parasites are so highly specialized that they,
like rickettsias and viruses, cannot be cultured outside of the cells that they parasitize, the
descriptions that have been published of these parasities were arranged in an appendix to
the order RickeUsiales in the sixth edition of the Manual (1948, p. 1121). However, these
protozoan parasites have been described by those who have studied them as being related
to quite a variety of genera of bacteria belonging in various orders of the class Schizomyceies .
Furthermore, these organisms are not in any sense of the word intermediate in character
between rickettsias and viruses, even though all are highly specialized intracellular para-
sites. For these reasons the parasites of protozoa are placed in this edition of the Manual
in an Addendum to Class II, Schizomyceies.
While onl}^ about one dozen species of these bacteria have as yet been described and
named, several additional species have been well described without having been named.
Still other species are known to exist. No special student of the group has as j^et attempted
to place these interesting organisms in relation to recognized families and genera of bacteria
more definitely than is indicated above. The organisms in question are, as yet, best known
to protozoologists and are rarely mentioned in textbooks of bacteriology. Their existence
suggests that other groups of invertebrate animals may suffer from similar bacterial dis-
eases as yet unknown. — The Editors.
GENERA AND SPECIES OF PARASITES OF PROTOZOA.*
I. Species placed in special genera:
Genus A. Caryococcus Dangeard, 1902.
(Compt. rend. Acad. Sci., Paris, 18^, 1902, 1365.)
Ca.ry.o.coc'cus. Gr. noun caryum nut, kernel, nucleus; Gr. noun coccus berry, coccus;
M.L. mas.n. Caryococcus nuclear coccus.
Spherical organisms parasitic in the nucleus of Euglena.
The type species is Caryococcus hypertrophicus Dangeard.
1. Caryococcus hypertrophicus Dan- 2. Caryococcus cretus Kirb}% 1944.
geard, 1902. (Compt. rend. Acad. Sci., Paris, (Univ. CaHf. Publ. Zool., 49, 1944, 240.)
i34, 1902, 1365.) cre'tus. L. p. adj. cretus visible, dis-
hy, per. tro 'phi. cus. Gr. pref. hyper over, cernible.
more than; Gr. adj. trophicus nursing; Spherules 1.0 to 1.5 microns or more in
M.L. adj. hypertrophicus overfed, causing diameter. Appear clear in preparations with
hypertrophy. usually a chromatic, sharply defined, cres-
Occurs in the nucleus as an agglomera- centic structure peripherally or interiorly
tion of close-set, spherical corpuscles. The situated, sometimes with two such bodies
nucleus increases considerably in volume, or several chromatic granules. Parasitic in
the chromatin is reduced to thin layers nucleus. The parasitized nucleus is enlarged
against the membrane, and the interior of only moderately or not at all, and the chro-
the nucleus is divided into irregular com- matin is altered but not greatly diminished
partments by chromatic trabeculae. in amount.
Parasitic in the nucleus of a flagellate Parasitic in the nucleus of a flagellate
{Euglena deses). {Trichonympha corbula) from the intestine
- Prepared by Prof. Harold Kirby, Jr., University of California, Berkeley, California,
October, 1946; revised by Prof. Bronislaw M. Honigberg, University of Massachusetts, Amherst, Massachusetts, March, 1955.
