Planktonic Foraminifera collected in coastal waters off southern California were maintained in agnotobiotic cultures for periods up to 3 months. Culture techniques developed in this laboratory sufficed to ensure the survival of healthy, floating specimens of young Globigerina bulloides d'Orbigny and other plankton for extended observation and photography after collection.

A standard routine was used at each collecting station. More than 1 gallon of sea water was pumped from a depth of 3 m. and the temperature recorded. Vertical plankton tows were made with coarse-(253-micron) and fine- (61-micron) mesh nets, using a slow return speed of about 5 m. per minute. The samples were diluted immediately in sea water and picked rapidly for Foraminifera and mixed planktonic algae onboard ship. The resulting specimens were placed in filtered sea water (five foraminifers per 4.5-ounce jar), packed in a basin with damp paper towels, sealed, and returned to the laboratory. There they were fed from established algal cultures, covered, refrigerated in constant light at 15° C., and changed the next day into filtered in situ sea water containing mixed algae.

Cultures were limited to five or less specimens per 6-ounce dish, and were changed regularly. Squares of plastic film were used to cover cultures, in order to

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retain moisture and relatively constant water conditions. The Foraminifera were fed mixed planktonic algae from cultures started at each station and subcultured into filtered in situ sea water.

Because G. bulloides was the most common species encountered in tows, it was predominant in the cultures. Young transparent specimens gave the best results. They commonly developed tenuous, elongate pseudopodia, measuring up to 10 times the test diameter in length, which supported the specimens in flotation for periods up to 3 months. Some specimens in culture developed into orbuline stages previously identified in the literature as Orbulina universa d'Orbigny. Other orbuline stages were collected in the tows. Most lived approximately 3 weeks, during which time they passed through a series of developmental stages. Changes in the morphology of the globigerinids and their orbuline phases were photographed.

Bright orange-yellow zooxanthellae were present in most of the plankton studied. They were most obvious in newly formed orbuline phases, as well as in healthy globigerinids, and appeared to be related in numbers to metabolic activity of the host organism.

Several radiolarian species from different families also were maintained floating for more than a month, and preliminary observations were made on their structures.

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