^L. rudis.^ A smaller species than the last. It is strong and coarse, with revolving grooves and ribs, or smooth, with interrupted whitish bands and spots. A very common variety of this species is much smaller than the typical form, being about one sixth to one fourth of an inch long, smooth, with white and yellowish spots on olive. It clings to the rocks near high-tide mark, and is usually found attached to its resting-place by a bit of hardened mucus. While the typical /L. rudis/ is heavy and banded, with a moderately high spire and no color, this [pg372] variety is thinner, with a higher spire and smoother surface, and has a color-scheme of decoration. It would be impossible to disconnect the two, for a large series of specimens will demonstrate beyond doubt, through every minute degree of variation, that the two forms belong to one and the same species. The station of /L. rudis/ is much the same as that of /L. litorea/, but the smaller colored variety of /rudis/ prefers quieter and more sheltered spots. It is occasionally found on reeds and grasses, on the piling of wharves, on large boulders above the line of algæ, and on algæ. It has been the writer's experience not to find /rudis/ and /litorea/ associated together. [Illustration: /Littorina palliata./] ^L. palliata.^ A low-spired, globular shell with a large, tumid, smooth body-whorl. The columella is flattened, curved below, and imperforate. The color is exceedingly variable, but is usually bright, shining olive, and this is especially the case with those individuals that find their station in the dense masses of algæ that form so conspicuous a feature of a low-tide scene on a rocky New England coast. From pure olive-green to yellow or bright red, with revolving black bands, seems a long chromatic leap, but it is not too great for the Designer of these pretty little globular shells. As a rule, the color of the shell simulates pretty closely that of the seaweed upon which it lives, and inexperienced eyes may easily overlook hundreds of specimens, all within close reach. The banded varieties are less common. The head of the animal is somewhat orange in color, the foot slate. The distinguishing features of this species are the smooth, globular shell, the low spire, the broadly flattened columella, and the orange-colored head of the animal. It is found on /Fucus/ between tides, and often associated with /L. rudis/, on the whole coast north of New Jersey. The three preceding species are distinctly boreal in their range, but their place is taken in southern Atlantic waters of the United States by the following exceedingly common species: [Illustration: /Littorina irrorata./]