Ovate, wedge shaped, flat; superior valve with longitudinal striæ; white, granulated, and rough; slightly tinged with purple near the beak. 2. Lima. The File Shell. Six species. No sinus or notch; the valves, thick and gaping, form a lateral opening; the ears are small, but distinct. Shell oval, more or less oblique, almost equivalve, with small ears, regularly gaping at the anterior part of the lower edge; summits anterior and distant; hinge longitudinal, without teeth; ligament rounded, almost exterior, inserted in a cavity of each valve; central muscular impression divided into three very distinct parts. Lima inflata. L. squamosa. L. glacialis. L. annulata. L. fragilis. L. linguatula. _L. squamosa._ The scaly Lima. Pl. 15, fig. 3. Answers to the above description, with valves ventricose, armed with vaulted scales. _L. fragilis._ The fragile Lima. Oblong ovate, very pellucid, delicately white, with longitudinal distinct striæ; lower margin denticulated, closely interlocking when the valves are closed. 3. Pecten. The Scallop. Fifty-nine species. The shells constituting this genus are found in all seas; they are well known, and many of them are very beautiful. The form is usually regular; their surface is adorned with elevated divergent ribs, varying in number from five to thirty, proceeding from the beaks and terminating at the margins in a scalloped outline. Some are equivalve, others have one valve flat and the other convex; the colours of the upper valve are brighter than those of the lower. There is considerable variation in the size and form of the ears, which in some species are equal or nearly so, but in others are unequal; some are so small as to be nearly indistinct. The ribs are variously diversified with beautiful colours and delicate checker-work; the margins are mostly crenated, and oftentimes beautifully coloured. These shells were formerly worn by Pilgrims on their hat or coat, as a mark of having been to the holy shrine in Palestine. Shell free, regular, thin, solid, auricled, equivalve, equilateral; summits contiguous; hinge without teeth; a ligamental membrane through all the length of the hinge, besides a short, thick ligament, almost entirely internal, which fills a triangular cavity under the summits; one sub-central muscular impression.