ABSTRACT
The swimming behaviour of the anemone Stomphia coccinea Müller has been described by several authors (Stephenson, 1935; Yentsch & Pierce, 1955; Sund, 1958; Wilson, 1959; Hoyle, 1960; Robson, 1961). Specimens from the region of Puget Sound and the San Juan Islands respond to contact with certain starfish or to suitable electrical stimulation with a characteristic sequence of activity. They retract, re-expand, detach from the substratum, and display a series of abrupt bending movements which may continue for several minutes. An inert recovery period is followed by re-attachment to the substratum. The only species so far known to provoke this response are the starfish Hippasteria spinosa Verrill and Dermasterias imbricata Grube. The world distribution of the genus Hippasteria overlaps to some extent that of Stomphia, which is a widespread North European-Arctic form, but Dermasterias is strictly indigenous to the north-west American coast. Neither starfish seems to affect the anemone in any other way, and the significance of this particular response is difficult to understand.
Unpublished observations.
