Page:Natural History, Mollusca.djvu/202

190 which the hoof-like body assumes, which fit it for lying on loose sand, without becoming deeply buried in it." I am inclined to believe that the original form of this egg-mass is that of a very broad ribbon, attached by one edge to a rock, like that of a Doris, in a spiral curve, the upper edge of the ribbon leaning outwards a little, so as to resemble a cup, and that the likeness to a horsehoof which Professor Harvey alludes to, and which I have myself observed, is seen only when the ribbon is torn away by the dredge, and turned upside-down. This curious mass of eggs was considered to be a zoophyte by the earlier naturalists, and was characterised as such by Gmelin, under the name of Flustra arenosa. Its true nature was first suspected by Mr. Boys, and was fully proved by Mr. Hogg, in 1833, who hatched the Natica from it.

The species of this genus are all carnivorous, boring holes into other shells and devouring their contents. Dr. Gould asserts that they are very voracious, and play a conspicuous part in devouring the dead fish and other animals which are thrown up by the tide. The small circular holes with which bivalve shells are often drilled, are the work of these snails, and made by them to gain an entrance to the animal apparently so well secured against such a foe. The foot can be expanded so as to envelope completely the objects on which they prey, for a long retention of it in its grasp is necessary, from the slowness with which they work their auger or spiniferous tongue.