Cestode worms of the family Onchobothriidae are parasites in the intestines of sharks. Dr. Janine Caira proposes to study the evolutionary relationships among the species of the family, and in the process identify those morphological features that are discordant with evolutionary relationships, in that they evolve independently in different lineages. Dr. Caira then proposes to analyze the degree to which these characters are adaptations to the mechanical attachment of worms to the shark. The proposed study has broad implications on several levels. The evolutionary study will lead to a more accurate understanding of the species of the family, an improved classification, and more reliable identification criteria. The study of attachment adaptation has potential for illuminating the process of coevolution, a subject of interest throughout biology.