Agnes now saw several shells lying scattered about, but she scarcely condescended to look at them, till at last, one appeared so curious that she could not help calling her mamma’s attention to it. It was a long narrow shell, something resembling the handle of a pocket knife. What she picked up, however, was only the half of what was evidently a bivalve-shell, and to Agnes’s great annoyance, it was by no means perfect. Mrs. Merton, however, told her that it was what was called a Solen, or Razor-shell, or, sometimes, a Sheath-shell, from its resemblance to the handle, or sheath of a razor. She also showed her the hinge that united the two valves together, and which, though very slight, was curiously formed. While Mrs. Merton was speaking, Agnes saw another shell nearly similar to the first, but smaller and prettier, and the little girl ran with great delight to pick it up. Just before she reached it, however, she saw it raise itself on one end, and then instantly disappear in the sand. [Illustration: _Fig. 29._ TRUNCATED GAPER. SOLEN, OR RAZOR-SHELL. COMMON COCKLE. THE KNEADING TROUGH. ] It is scarcely possible to express the astonishment and almost terror which seized Agnes at this sight; and she ran back to her mamma almost too frightened to ask the cause of what she had seen. Her mamma, however, explained to her that it was the nature of the animals belonging to these shells to bury themselves in the sand when they were alarmed; and she added, that the disappearance of the shell was a certain proof that it was inhabited. “Oh mamma!” cried Agnes, “how I should like to see the animal. Can’t we get it up out of the sand without hurting it?” “I am afraid not,” said Mrs. Merton; “for these animals have been known sometimes to descend to the depth of two feet, and I believe they generally go at least a foot beneath the surface, which is a greater depth than I could possibly dig to, with the point of my parasol, and I have no other instrument at hand.” “But then,” cried Agnes, “how will the poor solen return itself, for I suppose it will not always remain buried in the sand?” “If you will look attentively,” said Mrs. Merton, “you will see that the solen has left a little hole, by which he can return to the surface whenever he thinks proper, which no doubt will be as soon as we have disappeared;” and, in fact, when Agnes looked at the little narrow tube which the solen had left in the sand, she fancied she could see some slight appearance of its shining pinkish shell in the hole. Her mamma, however, would not suffer her to attempt to get the shell out, lest she should destroy the tube, and thus convert the poor solen’s retreat into its tomb. She, therefore, stood for some time looking at the hole in silence; and at last asked her mamma if there was not any way of bringing the creature out without injuring it.