ECOLOGY OF CRASPEDACUSTA-SOWERBII LANKESTER, A FRESHWATER HYDROZOAN

C. sowerbii Lankester, one of the few freshwater cnidarians, is distributed throughout North and South America, Europe, Asia and Australia. Little is known, however, about its ecology. The life history is reviewed and illustrated. North American field reports and major experimental works are discussed and analyzed, along with the present laboratory work. Environmental factors that are known to affect the organism, i.e., temperature and food, are discussed, as are some factors which must be studied further, i.e., pH, C02 tension and light. The direction for future field reports and experimental work is suggested.