They possess two pairs of nerve cords and often a statocyst.

An internal balancing organ called a statocyst ensures graceful movement.

The statocyst is therefore useful for telling the animal whether it is upside down or not.

Lower down near the undulating margin there are 4 short secondary tentacles, each with a statocyst on either side.

Acoels have a statocyst, which presumably helps them orient to gravity.

The statocyst is protected by a transparent dome made of long, immobile cilia.

The specimen does show the statocyst, however.

The shrimp with which he was experimenting innocently introduced iron filings into the statocyst.

A statocyst with a single otolith is attached dorsally to each pedal ganglion.

The sensory organs include a statocyst and, in some cases, very primitive pigment-spot ocelli capable of detecting light.

Each rhopalium is typically associated with a pair of sensory pits, a statocyst, and sometimes a pigment-cup ocellus.

Xenoturbella, a bilaterian whose only well-defined organ is a statocyst, was originally classified as a "primitive turbellarian".

In its adult stage, the worm lives off the excesses of its symbiotic algae, although the mouth is still present posteriorly to the statocyst.

Many invertebrates have a statocyst, which is a sensor for acceleration and orientation that works very differently from the mammalian's semi-circular canals.

The statocyst is a balance sensory receptor present in some aquatic invertebrates, including bivalves, cnidarians, echinoderms, cephalopods, and crustaceans.

The statocyst consists of a sac-like structure containing a mineralised mass (statolith) and numerous innervated sensory hairs (setae).

Each statocyst consists of a small sac lined with sensory cilia that detects the movement of a mineral mass, a statolith, under gravity.

Because the statocyst is located in the internal ear, it is more commonly, though less appropriately, called the otocyst (oh'toh-sist; "ear pouch" G).

The larva also has a statocyst and a pigmented cup above the mouth, which opens into a pharynx lined with small clefts opening into a surrounding atrium.

Statoconia (also called otoconia) are numerous grains, often spherical in shape, between 1-50 microns; collectively, statoconia are also sometimes termed a statocyst.

Equilibrioception in many marine animals is done with an entirely different organ, the statocyst, which detects the position of tiny calcareous stones to determine which way is "up".

The age of a giant squid can be determined by "growth rings" in the statocyst's statolith, similar to determining the age of a tree by counting its rings.

Its main component is a statocyst, a balance sensor consisting of a statolith, a solid particle supported on four bundles of cilia, called "balancers", that sense its orientation.

They are distinguished from related animals by the possession of a simple pharynx and intestine, and a single pair of lateral nerve cords, and by the absence of a statocyst.

To us that would be an upright standing position, so a utricle used for this purpose may be called a statocyst ("standing-pouch" G) and the bit of calcium carbonate is the statolith ("standing-stone" G).