From Ancient Greek ἀκτίς (aktis, “ray”) (genitive ἀκτῖνος (aktinos)) + -ula.
Actinula Sentence Examples
If the embryo is set free as a free-swimming, so-called planula-larva, in the blastula, parenchymula, or gastrula stage, then a free actinula stage is not found; if, on the other hand, a free actinula occurs, then there is no free planula stage.
Formation of archenteron and blastopore may, however, be deferred till a later stage (actinula or after).
In Ieptolinae the embryonic development culminates in a polyp, which is usually formed by fixation of a planula (parenchymula), rarely by fixation of an actinula.
- Free Actinula rhiza from which a polyp appears to be of Tubularia.
The polyp is regarded, on this view, as a form phylogenetically older than the medusa, in short, as nothing more than a sessile actinula.