Abstract
A large, undescribed species of scyphomedusa (Cnidaria, Scyphozoa) <br /><br />was sighted offshore, in bays, and washed up in large numbers on beaches of <br /><br />Southern California and northern Baja California, Mexico, during the summer of <br /><br />1989. Invertebrate associates, taken from two living but damaged medusae lacking <br /><br />tentacles and oral arms, included a pycnogonid sea spider and two species of <br /><br />mysidacean shrimp not previously reported associated with scyphozoans. These <br /><br />species probably became attached as the moribund medusae contacted the seafloor <br /><br />prior to washing ashore. Previously reported scyphozoan associates included a <br /><br />hyperiid amphipod and larval (megalopal) and juvenile brachyuran crabs of the <br /><br />genus Cancer. Photographs and video footage of living scyphomedusae allowed <br /><br />observations of the natural history of the medusae and of the behavior of juvenile <br /><br />crabs. The unique occurrence of this scyphozoan and its faunal associates is <br /><br />described and discussed along with other unusual local occurrences of species <br /><br />from other, mostly tropical, regions.
