The
stomodeum is also clearly visible, and there is an initial differentiation of the mandibules, maxillules, maxillae, and maxilliped primordia.
6.21 13
Stomodeum. 7.22 14 Complete formation of prototochal girdle and cilia.
(2,10,14) These cells are believed to derive from either the
stomodeum or the stomach, which is located in the neck close to the forming tongue at this stage of development.
3H, I), the extra-embryonic area disappeared after dorsal closure, and the
stomodeum direction was changed from upward to downward relative to the egg (Fig.
Although the larva has a
stomodeum, the gut is blind and the larva is packed with yolk granules (Fig.
Our conclusion, based on the location of the chaetal sac, the folding of the archenteron, and the relative locations of the
stomodeum, anus, and chaetal sac in the earliest swimming larval stage, is that the blastopore becomes the opening immediately adjacent to the chaetal sac in the larva and thus forms the anus.
5C, inset), and the majority of DAB staining is restricted to the
stomodeum cells and the cells that lie posterior to this structure (Fig.
Fully grown bipinnariae had ciliary bands divided into two loops; five conspicuous pairs of bipinnarian arms, which are hollow extensions of the body wall with ciliary bands arranged along the edge; and a complete gut formed by the fusion of the
stomodeum to the anterior tip of the archenteron.
The polychaete
stomodeum and the interrelationships of the families of the Polychaeta.
Concurrently the neurotroch becomes evident as a midventral mass of punctate fluorescence, with the densest reactivity just posterior to the
stomodeum. Label in the pygidium is becoming dense and organized except in the dorsal region where there is no fluorescence.
A ciliated
stomodeum formed on the ventral side of the unciliated ectodermal trunk directly below the apical cap (Figs.
As the
stomodeum forms, a ventral arc of muscle becomes apparent in the lower lip.