Welcome to the Sea Urchin Embryology Tutorial! This tutorial is part of an ongoing project designed to implement multimedia and computer-based learning materials in the university undergraduate classroom. The material presented here are NOT designed to replace either hard work outside of class wrestling with the dynamic nature of embryonic development, nor are they meant as a substitute for "wet lab" experience using a real microscope and real embryos. Instead, this tutorial is meant to supplement the presentation of standard videotape, laser video, digitized video and animation sequences in the traditional lecture period. A common comment is student evaluations is the wish for more opportunities to interact with the visual data presented in class in a more "hands-on" manner. This tutorial is designed as a beginning step in that process.