Doliolida

Order DoliolidaComplex alternation of generations between a solitary, asexually and sexually reproducing gonozooid and colonial, asexually reproducing oozooids; gill with several to many stigmata.Order SalpidaComplex alternation of generations between solitary, asexually reproducing oozooids and aggregated, sexually reproducing gonozooids. Pharynx leads

The thaliaceans (pyrosomes, dolioloids, and salps) are also pelagic. Their structure suggests that they are ascidians modified in adaptation to conditions in open water. They have specialized modes of reproduction, sometimes with a complicated alteration of sexual and asexual phases. Pyrosomes form long, tubular colonies. Dolioloids and salps…