In the succeeding shells, of the family _Cerithiadœæ_, the spire is also considerably produced, so much so that some of the species closely resemble the Turret shells, but they are distinguished by usually having an expanded lip, at least in the adult form; and the mouth is channelled in front, and sometimes also behind. The animals of the group have short muzzles that are not retractile, the tentacles are wide apart, and the eyes are mounted on short pedicels. The median teeth are arranged in a single row, with three laterals on either side of each. [Illustration: FIG. 175.--_Cerithium reticulatum_ AND _Aporrhais pes-pelicani_] _Cerithium reticulatum_ receives its generic name from its appearance to a small horn, and the specific name refers to the netted appearance of its surface due to the presence of numerous little tubercles arranged in rows--a feature that serves to distinguish it from the small Turret shells. It is a common shell, as is also the other representative of the family illustrated, but the latter is rendered conspicuous by the enormously expanded lip that has earned for it the popular name of Spout Shell. Its scientific name is _Aporrhais pes-pelicani_, and the application of the specific term will be understood when the shell is viewed from above, for the expanded lip is drawn out into long finger-like lobes that suggest the foot of a bird. This is a very solid shell, sometimes reaching a length of two inches; and the animal inhabiting it is carnivorous. [Illustration: FIG. 176.--_Aporrhais pes-pelicani_, SHOWING BOTH SHELL AND ANIMAL] We have yet some turreted shells to deal with, belonging to the family _Pyramidellidæ_, but they need not be confused with the preceding groups if carefully examined. In the first place, the aperture of the shell is very small; and the operculum, instead of being spiral, as in the turreted shells before mentioned, is imbricated or made up of parallel layers denoting that the growth took place on one side only. Another distinguishing feature is seen in the nucleus--that small portion of the spire that was developed within the egg--which is sinistral or left-handed. In addition to this, the animal has broad, ear-like tentacles, a retractile proboscis, and a lingual ribbon without teeth. The British species of this family belong principally to the genera _Odostomia_, characterised by a tooth-like fold of the columella; _Eulima_, containing small, white, polished shells with numerous level whorls; and _Aclis_, with little polished shells not unlike _Turritella_. [Illustration: FIG. 177.--1. _Odostomia plicata._2. _Eulima polita._ 3. _Aclis supranitida_]