ADDENDUM TO CLASS II 927 



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. 



