Covered with a rather lax structureless membrane (sarcolemma), which is spirally wrinkled when the muscle contracts. I am unable to verify Geza Entz's observations, adopted by Calkins and Delage.
Of the composition of cellulose (Halliburton, in Quart. Journ. Micr. Sci. xxv. 1885, p. 445).
As does the Hypotrichan Kerona polyporum.
Permanently ciliate in Hypocoma and Suctorella.
In this case the débris of the live prey torn up by the Cyclops on which they live.