Ma7J and Mollusks 15 



Sea Snails, ]anthina, in the Wentletraps, Epitonium, in some of the Mitras 

 and Olive shells and in the sea hares, Aplysia. These substances are known 

 to be irritating to fish and other would-be predators, and its purpose as a 

 defense mechanism seems most likely. Probably future experiments will show 

 that the egg capsules of Mjirex, loaded as they are with purpurase, are dis- 

 tasteful to fish and have an unusually high survival value. 



