1. Twarog, B. M. 1973. personal communication, Dept. of Biology. Tufts University, Medford, Mass. 02155
2. Resistance to tetrodotoxin and saxitoxin in nerves of bivalve molluscs
3. We acknowledge the assistance of M. Collins, M. Hayes, S. Huyler, S. O'Callaghan, C. Sullivan and T. Thorpe and the advice of Dr. E. Gilfillan and Dr. C. Martin
4. Supported in part by the State of Maine Department of Marine Resources, Mass. Science and Technology Foundation AEC Contract AT (11–1) 3024 and the Rockport Public Schools