Studies in Marine Biology. II. In vitro Culture of Zooxanthellae.

Single-cell algae (the so-called symbiotic zooxanthellae) living inter-stitially in a marine jellyfish and a sea anemone were isolated from the host tissue and cultured in vitro. 2. In culture the zooxanthellae gave rise to motile forms whose morphology clearly marked them as dinoflagel-lates. 3. Isolation procedures and some nutrient requirements for the in vitro culture of such zooxanthellae are described, as well as methods used for serial passage.