| Despite its good preservation, this single specimen did not show all aspects of the theca. |
| We may then suppose that the ancestral form was a monad with a theca which, in some progeny, assumed the form found in the Apusozoa. |
| This theca grows in the direction of the apex of the sicula, to which it adheres by its dorsal wall. |
| The theca around the column is smooth, sometimes with weak longitudinal muscles. |
| This elastic ring is a continuation of the stalk of the theca, which always bursts on the opposite side. |
| The costae, longitudinal ribs or rows of spines on the outer surface of the theca. |
