Comparative studies on holotrichous ciliates in theColpidium-Glaucoma-Leucophrys-Tetrahymenagroup

Abstract

In the last 30 years, at various laboratories in the United States, France and England, many strains of small holotrichous ciliates have been established in axenic culture for use in a widening variety of investigations of a physiological or biochemical nature. Since few of these organisms have been adequately described or properly identified by the workers employing them, thus making difficult meaningful comparison of the various experimental results reported, the need for morphological and taxonomical study has become increasingly apparent. At least twenty-nine such axenic strains of ciliates, considered members of a ‘Colpidium-Glaucoma-Leucophrys-Tetrahymenagroup’ because it has been principally to these four genera that the protozoa have been assigned in the past, are still in existence and twenty-six of them were collected for use in the present investigation. For accurate identification of such relatively undifferentiated ciliates the use of silver nitrate impregnation techniques, the value of which was recognized some years ago by Klein (1926) and stressed by Furgason (1940), is re-emphasized as being nearly indispensable. Details of buccal organelles and differentiated pellicular structures in other parts of the body are revealed precisely and with constancy.