Giant embryos and hatchlings of Antarctic nudibranchs (Mollusca: Gastropoda: Heterobranchia)

of development up to ready-to-hatch juveniles 2.5 mm in length. Based on their morphology and development in egg masses maintained in the laboratory, the embryonic period for B. hodgsoni is estimated to be up to 10 years, and for D. kerguelenensis 13 months. Thus, B. hodgsoni has the largest egg capsules and probably the largest hatchlings of any mollusc. Chemical analyses of D. kerguelenensis egg masses showed no trace of terpenoid acylglycerols, although these compounds were present in field-collected juveniles and adults. None of four sponges that likely serve as food for D. kerguelenensis had the glycerides, or their precursors, found in the nudibranch.