VAGELLI, A.A.: New observations on the asexual reproduction of Aurelia aurita (Cnidaria, Scyphozoa) with comments on its daptative significance.

A new reproductive mechanism has been observed in scyphistomae of Aurelia aurita. It is termed gemmation and it is referred to as an asexual mode of reproduction in which scyphistomae produce small and mostly spherical masses of cells called gemmae. These structures are generated internally by extrusion of the body wall tissue. In contrast to the budding process, gemmation produces ramets that do not develop adult scyphistoma morphology prior to their release, and they only do so after passing through a free-swimming period that lasts several weeks. In addition, a new budding process in A. aurita is reported. It is characterized by the external production of free-swimming buds, which also pass through a planktonic stage before settlement and metamorphosis occurs. A description of A. aurita life cycle is presented, including comments on its various modes of asexual reproduction, larval development, and their adaptative significance.