as well as from the report of others, that this showy Worm is usually found, a co-occupant with the Soldier of old shells. The fishermen of Weymouth prize this Worm for bait more than any other; and are so well aware of its habits that they commonly break all Whelks containing Soldiers, in order to extract the Nereis which they know is within. Dr. Johnston in his description of N. bilineata (Ann. N. H. July, 1839) has alluded to their occurrence together.
Besides the interesting fact of this mutual friendship, we learn somewhat from the above observation of the rapacity and carnivorous habits of the genus Nereis, already inferred from their anatomical structure. That the senses of this Worm are not very acute I infer from the following experiment. I dropped a piece of meat into the mouth of the Whelk-shell that was tenanted only by a Nereis, and watched the result. After a time the Worm protruded, not apparently induced so to do by any expectation of food, and though its head was often brought almost into contact with the flesh, it was evidently unconscious of the proximity; for it took not the slightest notice of it, and allowed it to remain untouched all day.
The graphic description of the Soldier going about on the beach, turning over and examining shells, and now and then trying how they would fit his body,—has been so often quoted that we are apt to think it is a common sight, and may be witnessed by any stroller on a shelly beach. Yet I think the fact has been very seldom seen; and I judge so from my never having seen any other than the one well-known
