The Ultrastructure of the Muscle System of Stomphia coccinea

Abstract

In the forty years since Pantin’s classic studies, there have been considerable changes in our concepts of the neuromuscular organization of sea anemones. In large part this is the result of behavioral studies illustrating the elaborate shell-climbing behavior of Calliactis (Ross and Sutton, 1961a, b) and swimming in Stomphia (Yentsch and Pierce, 1955; Sund, 1958). A great deal of attention has since been devoted to the structure (Robson, 1961, 1963; Peteya, 1976) and physiology (Ross, 1957; Hoyle, 1960; McFarlane, 1969a, b; Lawn, 1976; Lawn and McFarlane, 1976) of the nervous and neuroidal systems controlling these patterns; however, our knowledge of the muscular organization of anemones is still quite limited. We have undertaken an ultrastructural study of the muscle system of Stomphia coccinea in a search for anatomical correlations to the general physiology of actinians and to the swimming behavior of Stomphia. This first paper is a report of the occurrence of consistent differences in the structure of muscle fibers from the different endodermal muscle fields of Stomphia.