Cross sections of a pair of basal bodies showing the triplet makeup of the 9 fibers; only one microtubular fiber is complete in each triplet while the other two microtubular fibers share some subunits...

Cross section of the oral region (buccal cavity) posterior to the vestibulum. The cytopharynx is beginning on the dorsal surface and the ribbed wall, peniculi and quadrulus are present on the right an...

Septa of bordering alveoli when lying in the plane of section exhibit pores at their outer margins closest to the plasma membrane. This shows that there is physical continuity between the lumens of al...

Dictyosomal elements of the Golgi complex consist of a layer of coated transition vesicles next to a specialized area of ER called the transition zone and two or three highly fenestrated layers of cis...

Detail of the filamentous reticulum along the left side of the cytopharynx from which cytopharyngeal ribbons arise next to its nodes. Quadrulus associated ribbons lie between the filamentous reticulum...

Nucleoli in a macronucleus of a cell undergoing micronuclear division. The nucleolus appears to have an organized surface layer composed of parallel threads of subunits. These may be developing riboso...

A cell with a flat alveolar sac system. It is not clear why some cells have expanded alveoli and others have flattened alveoli. Cacodylate buffered fixative. TEM taken on 2/3/69 by R. Allen with Phil...

Developing trichocyst containing a paracrystalline core surrounded by amorphous material and an autophagosome containing mitochodrion. TEM taken on 1/25/74 by R. Allen with Hitachi HU11A operating at ...

Cross section through the more anterior part of the oral region showing the four more loosely spaced rows of cilia making up the quadrulus and more compact cilia of the peniculi on the left hand wall ...

Cross section of the oral region (buccal cavity) posterior to the vestibulum. The cytopharynx is beginning on the dorsal surface and the ribbed wall, peniculi and quadrulus are present on the right an...