Fig. 92.—Mactra: a, foot; b, c, siphons.
The shells are famous for their beauty, the polished valves and their marvelous tints presenting attractive combinations. The common mactra (Fig. 92), the cockle (Fig. 93) with its deep radiations, the gorgeous pectens of the South, the splendid pearl-bearing shells, all tell a wonderful story of the resources of nature, and emphasize the fact that the smallest and most inconspicuous animals vie with the larger forms in beauty of shape and color.
Fig. 93.—Cockle.
XII. THE UNIVALVES
