THE UNIQUE, WIDELY DISTRIBUTED, ESTUARINE SEA-ANEMONE, NEMATOSTELLA-VECTENSIS STEPHENSON - A REVIEW, NEW FACTS, AND QUESTIONS

The small, burrowing, edwardsiid sea anemone Nematostella vectensis is widely distributed in estuaries and bays. Most typically it occurs in pools in marshes though it may occur subtidally as well. We have comp iled records of its occurrence in North America from Nova Scotia to Ge orgia along the shores of the Atlantic Ocean, from Florida to Louisian a in the Gulf of Mexico and from California to Washington on the Pacif ic coast. To date we have found no records of its presence in Alabama or Texas, though it is present in all other of the contiguous coastal states of the United States. The species also occurs in England. We ha ve obtained living specimens from many locations and have crossed fema les from England Maryland, Georgia, California, Oregon, and Washington with mates from Nova Scotia, Maryland, Georgia, and Oregon. These 24 crosses all yielded viable first-generation anemones that in turn prod uced second-generation animals. We accept this as proof that this wide ly distributed anemone is a single species. We have obtained living N. vectensis from 11 areas. Of these, only samples from Maine, Maryland, Georgia, and Oregon contained both sexes. The sample from Nova Scotia was all male and our samples from England, New Hampshire, California, and Washington were all female. We hypothesize that the unisexual sam ples were from clones resulting from asexual reproduction in this spec ies.