Behavior and flagellar currents in coronate polyps (Scyphozoa) and comparisons with semaeostome polyps

Abstract

1. On morphological and behavioral grounds as well as on the basis of flagellar currents, three scyphopolyp types can be recognized if one restricts oneself to the Orders Coronatae and Semaeostomeae. The coronates include the flower-likeStephanoscyphus racemosus and the rest which are called the typical sort. 2. The three polyps could be compared, body region by region, with respect to their responses to touching with a glass rod. A previous study showed that the body regions of a semaeostome polyp were all neurologically isolated. The typical coronates, on the other hand, show more neurological interaction. When a tentacle is strongly stimulated, all the tentacles shorten and the polyp retracts. 3. The calyx-stalk region of the semaeostome polyp and the typical coronate polyps are rather insensitive to touch but the stalk ofS. racemosus is sensitive. 4. The three polyps were compared, body region by region, with respect to flagellar currents as shown by the movement of carmine particles in sea water. Coronate polyps do not have tentacular flagellar currents whereas the semaeostome polyp has a current directed centrifugally. 5. Coronates can defecate. Sometime after a meal the head end hyperextends laterally and the flagellar currents along the filaments (four special bands in the coelenteron) reverse to beat towards the head thus clearing the debris from the coelenteron. This seems to be followed by a retraction of the polyp. 6.Aurelia was not observed to defecate but it likely does so; however, when it is turned inside-out the flagellar currents along its filaments can be made to reverse after prodding.