Casper the Ghost does not exist, in the eyes of science, that is, but for a group of divers he is very real - they see him all the time. A white, worm-like organism, his usual haunt is off the coast of Cape Town, hanging around the sponges.Casper is on a growing list of marine animals waiting to be described. The problem with Casper, said Georgina Jones, a member of the Southern Underwater Research Group, is that no one knows to which botanical family he belongs."Although it has a mouth, there is no trace of a stomach or any other organ. They want to try to identify it using DNA analysis," she explained.Casper, it is suspected, wraps himself around his food, probably sponges, and just absorbs it.Over the past decade members of the research group have discovered between 10 and 15 new species. Last year they discovered a tiny shrimp they have called the stargazer mysid.Professor Charles Griffiths, of the University of Cape Town, was unable to identify the mysid when it was handed to him by the group's founder, Guido Zsilavecz.Griffiths believes that 30 new marine species are found in South African waters annually.Zsilavecz recently also discovered a soft-bodied sea slug of the type known as a nudibranch. It has large green lobes, which he says resemble the Sydney Opera House."It is amazing that we are still finding so many new species in heavily dived waters such as False Bay, right on our doorstep," Griffiths said.Another odd new species to which Jones gave an unusual nickname was the jumping sand - an amphipod that makes a home for itself by gluing grains of sand together.According to Jones more species are being discovered as more recreational divers take cameras with them.Previously, new specimens were discovered by trawling the oceans but animals living under overhangs were often missed.The list of animals waiting for an academic to describe them is lengthening...