Opercularia is named for a ciliated flap (operculum) that is adoral to the opening to the oral region. However, this operculum is pulled back into the body when the myonemes are fully contracted as in...

A high resolution overview of Opercularia coarctata showing that cytostome divides the peristome from the cytopharynx. The cytopharynx starts where the alveoli end in the oral region. TEM taken on 6/1...

The cytostome of Opercularia divides the peristome from the cytopharynx. The cytopharynx starts where the alveoli end in the oral region. TEM taken on 6/13/69 by R. Allen with Philips 300 operating at...

A contractile vacuole in systole. The CV has collapsed into vesicles and tubules. Three CV pores can be seen where the CV meets the pellicle. Smooth membrane cisterna surrounds some cytoplasm, possibl...

High resolution image of the contractile vacuole and the spongiome decorated tubules showing V-type proton pumps extending from the cytosolic side of the tubules; also detail of the micronucleus. TEM ...

High resolution image of the contractile vacuole in diastole (filling phase). Decorated spongiome surrounds the CV. The macronucleus, micronucleus, cytopharynx, and basal bodies of perioral membranell...

This figure shows the connection between the peristome and the food vacuole forming zone where the alveoli end. The cytostome is the opening that connects these two zones. TEM taken on 6/13/69 by R. ...

Nuclear pores in face view of Opercularia coarctata. TEM taken on 6/13/69 by R. Allen with Philips 300 operating at 60kV. Neg. 14,800X. Bar = 0.25µm. A print of the negative was scanned and processed...

An image of the contractile vacuole and the spongiome decorated tubules showing V-type proton pumps extending from the cytosolic side of the tubules; also detail of the micronucleus. TEM taken on 6/10...

This section is cut at a level where the macronucleus is folded so it appears to be in 2 parts and where the micronucleus is visible. Contractile vacuole, perioral kinetids, and the peristome is evide...