Name of studied species and author of study | Fate of larval organs | |||
---|---|---|---|---|
Preoral lobe | Tentacles | Telotroch | Protocoel | |
“Actinotrocha A” (probably larva of Phoronopsis harmeri) [22] | transforms into small unpaired remnant that gives rise to the adult epistome | completely turns into definitive tentacle | retained for at least 4 days and then degenerates | ? “…the existence of a coelomic epithelium in the juvenile epistome is impossible confirm or deny…” |
is partly retained as two lateral remnants, which contribute to the future formation of the epistome | undergo partial reduction: the postroral ciliated band degenerates. Larval tentacles change neither in length nor number | retained for 9 days and then disappears | retained, but greatly reduces in size | |
retained as fold of the larval episphaere near the mouth and then turns into epistome | completely destroyed; adult tentacles arise from anlagen of definitive tentacles, which are located under the larval | is drawn into the digestive tract and becomes hindgut | cells, which form the lining of the preoral lobe are completely retained and give rise to the definitive protocoel | |
Phoronis muelleri [39] | ? | completely destroyed; adult tentacles arise from anlagen of definitive tentacles, which are located under the larval | is drawn into the digestive tract and becomes hindgut | protocoel is present neither in larva nor adult |
Phoronis psammophilla [24] | retained as fold of the larval episphaere near the mouth and then turns into epistome | completely destroyed; adult tentacles arise from anlagen of definitive tentacles, which are located under the larval | retained for several days and then disappears | ? |
Phoronis pallida [25] | completely destroyed | undergo great cellular death. Accordingly to figures, the length and number of larval tentacle greatly reduce. Definitive tentacles apparently arise from proximal portions of larval tentacles. | ? can not be observed by SEM in juvenile just after the completion of metamorphosis. Apparently, the telotroch is drawn into the digestive tract | ? |
“Actinotrocha C” [38] | completely destroyed | thickened proximal portions are retained through metamorphosis and give rise to definitive tentacles | is drawn into the digestive tract | ? |