The 6 naupliar stages and 1 cyprid stage of B. eburneus are described from nauplii successfully reared, both individually and in mass culture, on Chlamydomonas sp. and Arbacia eggs. The number of exuviae was used as the main criterion for the number of stages. Size, spine structure, and appendage setation are given for each stage. Duration of the 6 naupliar stages is as follows (1) 15 minutes to 4 hours; (2) 1 - 2 days with an average of 1 day; (3), 1 - 4 days with an average of 1.5 days; (4), 1-4 days with an average of 2 days; (5), 1-5 days with an average of 2.6 days; and (6), 2-4 days with an average of 2.5 days. The cyprid stage ranges from 1-14 days, but successful attachment was observed only in those which settled 1-3 days following the final naupliar molt. The over-all larval development in the laboratory, at 26 C, ranges from 7 to 13 days. Successful metamorphosis and attachment was observed in 16.3% of the 121 nauplii studied under segregated conditions.