Polyp-stage sentence example
- In Trachylinae the development produces always a medusa, and there is no polyp-stage.
- The Trachylinae, on the other hand, are above all oceanic forms, and have no polyp-stage, and hence there is typically no alternation in their life-cycle.
- In Trachylinae the polyp-stage is passed over, and is represented only by the actinula as a transitory embryonic stage.
- This must not be taken to mean, however, that the medusa is derived from a sessile polyp; it must be regarded as a direct modification of the more ancient free actinula form, without primitively any intervening polyp-stage, such as has been introduced secondarily into the development of the Leptolinae and represents 'a revival, so to speak, of an ancestral form or larval stage, which has taken on a special role in the economy of the species.
- The possession of a polyp-stage by Limnocodium and Microhydra furnishes an argument against placing them in the Trachylinae.Advertisement