Development of the sea nettle Chrysaora quinquecirrha (scyphozoa, semaeostomeae)

The development ofChrysaora quinquecirrha from the newly-liberated ephyra through the medusa stages is described. Studies on the development of specimens from nature were correlated with observations on laboratory-reared medusae. Growth was followed through six stages, successive stages being characterized by the appearance of or change in a given morphological character. Young ephyrae were similar to those ofC. melanaster, having slender, pointed lappets and deeply cut ocular clefts. Medusae having one, three, five, and seven or more tentacles per octant were observed. The number of lappets increased following an increase in the number of tentacles. This confirms that the number of tentacles and lappets is unreliable as a criterion for generic distinction in the Pelagiidae.