"I think of a statocyst
as an inside-out tennis ball," explained Dr Mooney.
Then the shaking causes the snails statocyst
to release GABA, which binds to the neuron.
These analyzed specimens of Gonionemus have: around a 10 mm width, four radial channels, a manubrium shorter than the umbrella cavity, a mouth with four lips slightly crenulated, four folded gonads along radial channels leaving the distal part free, between 40 and 44 hollow tentacles, each tentacle has ring-like nematocyst clusters and adhesive pads near the distal end, and one or two statocysts
between successive tentacles enclosed in mesoglea near ring canal with a single endodermal club.
The "Veliger" stage appeared after eight to thirteen days and had well developed larval structures (bilobed veil, operculum, statocysts
, foot, columellar muscle, larval heart) and a hardened globular proto-shell.
A weight-and-springs mechanical simulation of the statocyst
was built to help interpret the data on living statocysts
Serrate setae were found only on the statocysts
, which appear during larval stage VII.
The main diagnostic characters of Lovenella are the medusae with indefinite number of statocysts
and polyp with hydrotheca well demarcated by a basal line, separating it from the operculum (Fraser, 1944; Kramp, 1959; Bouillon et al., 2004).
puniceus shows simple morphology; it has paired palps and pygidial lobes, but no eyespots, nuchal organs, statocysts
, or ciliary rings dorsoanteriorly--an exceptional finding in this group.
rubra, aELH immunoreactivity was found in neurosecretory cells of cerebral and pluropedal ganglia, statocysts
, and trabeculae of female gonads (Cummins et al.
Gravity receptors, known as statocysts
in aquatic invertebrates, are considered to have evolved from underwater vibration receptors (Horridge, 1969, 1971) and to be the earliest true sense organs (Bullock and Horridge, 1965).
No immunoreactivity was observed within the statocysts
. As well, no difference was observed in peptide distribution in the neural tissues between female or male H.
Unlike the simpler marine invertebrate vestibular systems like that of nautilus, squid statocysts
contain both primary and secondary sensory cells (Williamson, 1990; Burighel et al., 2011).