Peristaltic waves of tubicolous worms and the problem of irrigation in Sabella pavonina

Abstract

A simple scheme is presented to illustrate four possible kinds of locomotory peristalsis in worm‐like animals. The application of this scheme to real animals is discussed. Peristaltic waves may be of constriction or dilatation. A continuous body cavity enables the worm to regulate both speed and direction of travel by controlling the relative tonus of its body wall muscles. Thus peristaltic waves can be used to pump water without causing locomotion. Sabella irrigates its tube by peristaltic swellings but the coelom and intestine are sub‐divided by entire septa. Anatomical and morphological features which allow the shortest, widest segments forming a “piston” to slide down the tube and the narrower elongated segments to grip its walls are considered. In this way the construction of the typical body segment is given a functional explanation. The functions of septa in annelids are discussed.

What is bioturbation? The need for a precise definition for fauna in aquatic sciences

“…Subsequently, both terms were used frequently in aquatic physiological and ecological literature (e.g. Mettaw 1969, Gamble 1970, Hoffmann & Mangum 1972, Foster-Smith & Shillaker 1977 -and some authors even switched between ventilation and irrigation (Dales 1961, Dales et al 1970. No consensus for a common usage and distinction between them has ever been reached.…”

“…Such blind-ended burrows can be problematic when their inhabitants need to ventilate for respiratory purposes. Many species have the capacity to propel water into the burrow by locomotory peristalsis of the body (Mangum 1964, Mettaw 1969, Giangrande 1991. It is not fully clear how the exchange of water occurs for many malda nid and terebellid species occupying impermeable co hesive sediments, but it probably occurs through relatively slow internal circulation or bidirectional water flow within the burrow (Fig.…”

LOCOMOTION OF THE HOLOTHURIANEUAPTA LAPPAAND REDEFINITION OF PERISTALSIS

“…Longitudinal contraction peristalsis is a wave of contraction of only longitudinal muscles that is unrelated to locomotion. Sabella uses such a wave to irrigate its tubule (Mettam, 1969). Starting at one end of the body, a wave of longitudinal contraction shortens constant volume segments causing dilation.…”

“…In the former, contraction of circular musculature does not involve entire bands or rings of circular muscle as is the case for the latter. (Mettam, 1969). In this type of locomotion (Wells, 1949) Retrograde non-overlapping peristalsis is the method of locomotion of earthworms and is described in detail by Gray and Lissman (1938), Clark (1964) and Child (1901.…”

Locomotory and other movements of the trunk of Bonellia viridis (Echiura, Bonelliidae)

“…Suffice it to mention the work of Wells (1944;1949a, b ;1954), Trueman (1966a,b),and Seymour (1970;1971) on ArenicoZu; that of Clark & Clark (1960) on Nephytys;Mettam (1969) on Subellu;and Elder (1973~) on Polyphysia. Clark (1964), Gray (1968) and Trueman (1974) provide reviews and theoretical discussions.…”