The zygote develops into a planula larva which swims by means of cilia and forms part of the plankton for a while before settling on the seabed and metamorphosing into a juvenile polyp. Some planulae contain yolky material and others incorporate zooxanthellae, and these adaptations enable these larvae to sustain themselves and disperse more widely. The planulae of the stony coral "Pocillopora damicornis", for example, have lipid-rich yolks and remain viable for as long as 100 days before needing to settle.