Page:Natural History, Mollusca.djvu/179

Rh after the manner of the spots on the cephalopodous mollusca, or, to use a more familiar instance, somewhat in the same way that the hues of a turkey-cock's wattle vary.

Mr. Arthur Adams, however, remarks on this statement: "Although I have examined hundreds of Cypræa tigris in a living state, I never saw those changes of colour in the mantle of the animal described by Mr. Stutchbury."

The form of a cowry-shell is so peculiar, that no one, on first taking it into the hand, would suspect that it is modelled on the same plan as the cones and olives with which it is frequently associated. Yet the structure is essentially the same, and in the youth of the shell the resemblance is manifest, a young cowry being so like an olive as to present no peculiarity worth notice. In the course of growth, however, important changes in the external shape occur, chiefly by the development of the outer lip, and the deposition of the surface-enamel. Mr. Gray defines three stages in the growth of Cypræa exanthema. In the first the shell is generally smooth, of a pale greyish colour, or with three transverse bands, and the upper part of the inner lip is smooth and convex, the lower part flat or concave; the outer lip is thin. The accompanying figures represent this stage.

In the next stage the shell begins to assume