These larvae all bear prototrochal, telotrochal
, and neurotrochal ciliary bands, as well an apical tuft of cilia at the anterior end.
Metamorphic stages were scored according to the following criteria, documented previously in Santagata (2002): stage one--partial histolysis of hood, telotrochal
cells, and the larval portion of the tentacles; stage two--complete histolysis of larval tissues and partial eversion of the juvenile trunk sac; stage three--larval gut pulled inside the juvenile trunk sac, but portions of the larval trunk epithelium not completely pulled into the juvenile body; stage four--all previous events plus the larval trunk epithelium completely pulled into the juvenile body.
In contrast to the labeled prototroch, there is not yet a distinct band of telotrochal label (Fig.
These include well-developed prototrochal and telotrochal bands, and a distinct neurotroch--a midventral cluster of cilia beginning posterior to the prototroch and terminating a short distance anterior to the telotroch.
A wide telotrochal
band forms on the otherwise uniformly ciliated ball; there is no ciliated apical tuft.
A few closely spaced circular fibers also become visible in the telotrochal region.
1c), filling the gap between the developing circular muscles and telotrochal bands.