actinotrocha


Also found in: Dictionary, Wikipedia.

actinotrocha

[‚ak·tə·nō′trō·kə]
(invertebrate zoology)
The free-swimming larva of Phoronis, a genus of small, marine, tubicolous worms.
Mentioned in ?
References in periodicals archive ?
Although differences in body organization prevent exact comparisons of body size, some echinoplutei with 6 to 8 arms are similar to this actinotrocha in both body length and ciliary band length (McEdward, 1984, 1986).
A functional and structural equivalent of the oral hood is unknown for the larval forms most closely resembling the actinotrocha.
The Reynolds number for flow produced by an actinotrocha lifting its hood is less than one.
Previous accounts of feeding by actinotrochas have focused on the operation of the lateral, laterofrontal, and frontal ciliary tracts on the tentacles.
Actinotrochas can ingest large dinoflagellates and other prey that are large relative to the width of the tentacle (Lebour, 1922; Herrmann, 1976).
When actinotrochas had ingested many particles, more particles passed the tentacles without a hood lift, and when they were disturbed, there were more hood lifts without the presence of a particle.
Lengths of cilia of actinotrochas of Phoronopsis viridis at the 14-tentacle stage were measured from video images.
The actinotrochas appear to have two active responses to particles, with the ciliary one acting before the hood lifts.
The actinotrochas do have laterofrontal cilia (Hay-Schmidt, 1989), but our videorecorded images were insufficiently clear for direct observation of sieving by those cilia.
Other measured velocities were slower and overlapped estimates for transport by cilia alone on animals with ciliary bands like those of actinotrochas.