"The pholas, I said, ma'am," he replied. "The `pholas dactylus,' as scientific people call it, which, until Gosse, as I said, discovered its mode of action, was quite a puzzle to every one; although, now that the mystery is out, all wonder it was not cleared up before! If you look at the head of the shell, you'll see it is provided with a regular series of little pointed spines at the end of the upper portion. These spines are of a much harder material than the main part of the shell, and are fixed into it, as you could notice better with a microscope, just in the same way as the steel points for the notes of any air are attached to the barrel of a common musical-box, projecting like so many teeth." "Yes, I can see them," observed Bob, who was listening attentively. "Look, Nell!" "Well, then," the Captain went on, "besides this toothed head of his, the animal is provided with a sucker at his mouth, by which he can hold on to any wooden pile or stonework he may wish to perforate so as to make his nest inside; and, gripping this firmly with his sucker and working the head of his shell slowly backwards and forwards with a sort of circular rocking motion, he gradually bores his way into the object of his affections, getting rid of the refuse he excavates by the aid of a natural siphon that runs through his body, and by means of which he blows all his waste borings away--curious, isn't it?" "Very," said Mrs Gilmour; while the children, equally interested, wanted to learn not only all the Captain could tell them of this peculiar little animal, but also everything he knew of the other wonders of the shore. "Sure I wish I knew all you do, Captain!" But, if the Captain was learned and good-natured, the children taxed his patience, Miss Nellie especially. She had not lost any time in setting about making that collection of shells which she had mentioned to him in confidence when coming down in the train it was her intention to begin as soon as she got to the sea; and, all the time he had been speaking of the little crabs and other things, she had been busily gathering together all sorts of razor shells, pieces of cuttle-fish bone, cast-off lobsters' claws, and bits of seaweed, which she now proudly drew his attention to, expecting the old sailor's admiration. He was, on the contrary, however, extremely ungallant. "All rubbish!" he exclaimed on her asking him if he did not think her pile of curiosities nice. "But, those corallines, young lady, are good. They were long supposed to belong to the animal world, like the zoophytes; instead of which they are plants the same as any other seaweed. When that little branch you have there is dry, if you put the end of it to a lighted candle, it will burn with an intense white flame, similar to the lime-light, or that produced by electricity." "We'll try it to-night!" said Bob emphatically. "We'll try it to- night!"