Image of the pellicle of Opercularia coarctata. Indentations of the plasma membrane penetrate the alveolar membranes end as coated pits. These pits are also known as pellicular pores are homologous to...

This freeze fracture view of the pellicle of V. microstoma near the aboral end of the zooid shows the region where the width of each circumferential alveolus is narrower and thus the strings of fractu...

This group of micrographs illustrate the ultrastructural characteristics of the middle layer of the three meningeal layers that cover the central nervous system. The arachnoid cells contain abundant i...

This group of micrographs illustrate the ultrastructural characteristics of the middle layer of the three meningeal layers that cover the central nervous system The arachnoid cells contain abundant in...

In this image a portion of the true surface of the plasma membrane is exposed where the culture medium has been etched away. The IMPs of the plates can also be viewed less distinctly on the true surfa...

Detail of cell surface structures. The cell is covered by the plasma membrane and outer alveolar sac membrane which is separated from the inner alveolar sac membrane by an extensive alveolar space. Ci...

This group of micrographs illustrate the ultrastructural characteristics of the middle layer of the three meningeal layers that cover the central nervous system. The arachnoid cells contain abundant i...

A high resolution view of the left side of the buccal cavity. It is covered by the plasma membrane, alveoli and a single partial layer of microtubules. Specialized cytoplasm lines the posterior end of...

In addition to plates the plasma membrane contains IMPs on its P-fracture face in ring or parenthesis shape at sites of trichocyst secretion. A ring actually consists of two circles of IMPs and signif...

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...