Nemerteans are common invertebrates along coastlines in both temperate and arctic climates throughout the world. Amphiphorus imparispinosus is a carnivorous member of this phylum that is found abundantly in the intertidal areas of the Oregon coast. As in many other invertebrate phyla, endocrine integration within the nemerteans is thought to be accomplished by neurosecretory mechanisms. In Amphiphorus the presence of these neurosecretory systems has not been previously shown. This project was undertaken to determine if neurosecretory cells are present within the central nervous system of this species and. further, to examine seasonal changes in the number and appearance of these cells. The second objective of this research was to determine the reproductive cycle of Amphiphorus and to examine a possible correlation between this cycle and seasonal changes in the neurosecretory system.