This project was initiated the previous year under a LSF funding. Its purpose was to provide a detailed descriptive, experimental and molecular study of aplacophoran embryology and larval development in the context of the current macro-evolutionary and developmental issuses. Research was to focus on the aplacophoran chaetoderm Chaetoderma nitidulum which is readily available at Kristineberg Marine Research Station. Aspects of aplacophoran development to be examined were the following: 1. Basic embryology and larval development. 2. Specification of the dorsal-ventral organizer and mesoderm. 3. Development of the larval and adult musculature systems and larval sensory organs. 4. Expression pattern of the engrailed gene and protein.