Magilus

Magilus, a remarkable Gasteropod found on the coral reefs of warm eastern seas. The young animal settles on the growing coral at the obvious risk of being gradually surrounded and smothered. This is avoided, however, by an entire change in the form of the shell, which is diverted from its original spiral type and grows out into a long irregular tube. 'A neck-and-neck race is kept up until the mollusc or the coral dies.' As the tube lengthens sometimes to 2 or 3 feet the animal shifts into it completely, and the original whorls are filled up with lime.