Life Cycle of Tripedalia cystophora Conant (Cubomedusae)

Abstract

THE Cubomedusae, commonly called “box jellies” or “sea wasps” because of their shape and, for some, their severe sting, are inhabitants of neritic tropical regions of the oceans. Though they have been known for more than 200 yr and the morphology of several species has been investigated¹, little is known of their life histories. Conant¹, in Jamaica, was able to rear the planula of Tripedalia cystophora to a four-tentacled polyp. Okada², in Japan, reared Carybdea rastoni to approximately the same stage. In neither case did the polyps live to an age which revealed their unusual nature. The opinion, held by many zoologists, that the Cubomedusae are an aberrant order of the Class Scyphozoa has therefore derived from a knowledge of the medusa generation alone. This belief, and the view of some authors^3–6 that the polyp is the stem form of all recent Cnidaria, have led to efforts to elucidate the life cycle of a member of this order.