STRUCTURE AND BEHAVIOR OF FRITILLARIA (TUNICATA, LARVACEA)

Fritillaria pellucida is close to neutral buoyancy, and feeds by a combination of tail movements and ciliary activity. The electrical correlates of these patterns of activity are described, and it is shown that the tail (controlled by the caudal ganglion), is capable of a variety of kinds of movement, which succeed each other in a stereotyped manner. Ultrastructural observations of the different kinds of ciliated cells associated with feeding show that those of the lower lip are sensory cells, linked to the central nervous system by the axons of central cells. The ciliary rings are under nervous control; ciliarymotor synapses are probably cholinergic. An unusual ciliary valve lies at the junction of oesophagus and stomach, but the cilia of this valve, and those of the pyloric ring, are probably not under nervous control. © 1979, Marine Biological Association of the United Kingdom. All rights reserved.