Mechanisms of Development in the Polyclad Turbellaria: A Key to Understanding the Evolution of Development in the Spiralia (B. Boyer).

Cellular Patterns and Morphogenesis in Early Development of Freshwater Pulmonate Snails, Lymnaea and Physa (Gastropoda, Mollusca) (J. Morrill).

The Initiation of Development in Chaetopterus (W. Eckberg & W. Anderson).

Mechanisms of Segmental Pattern Formation in Drosophila melanogaster (S. Small).

Development of the Central Nervous System in Drosophila (D. Smouse).

Recent Advances in Early Development of the Sea Urchin Embryo (S. Ernst).

The Morphogenesis of the Skeletal System of the Sea Urchin Embryo (C. Ettensohn, et al.).

Biogenesis and Function of Cortical Granules in the Sea Urchin Egg (G. Wessel).

Development of Ascidian Muscles and Their Evolutionary Relationship to Other Chordate Muscle Types (T. Meedel).

Indexes.