aculeatum, which had escaped that rolling on the sand fatal in old age to its delicate spines, and which equalled in colour, size, and perfectness the noble one figured in poor dear old Dr. Turton's "British Bivalves." Besides, aculeatum is a far thinner and more delicate shell. And a third species, C. echinatum, with curves more graceful and continuous, is to be found now and then with the two former. In it, each point, instead of degenerating into a knot, as in tuberculatum, or developing from delicate flat briar-prickles into long straight thorns, as in aculeatum, is close-set to its fellow, and curved at the point transversely to the shell, the whole being thus horrid with hundreds of strong tenterhooks, making his castle impregnable to the raveners of the deep. For we can hardly doubt that these prickles are meant as weapons of defence, without which so savoury a morsel as the mollusc within (cooked and eaten largely on some parts of our south coast) would be a staple article of food for sea-beasts of prey. And it is noteworthy, first, that the defensive thorns which are permanent on the two thinner species, aculeatum and echinatum, disappear altogether on the thicker one, tuberculatum, as old age gives him a solid and heavy globose shell; and next, that he too, while young and tender, and liable therefore to be bored through by whelks and such murderous univalves, does actually possess the same briar-prickles, which his thinner cousins keep throughout life.
Nevertheless, prickles, in all three species, are, as far as we can see, useless in Torbay, where no wolf-fish (Anarrhichas lupus) or other owner of shell-crushing jaws wanders, terrible to lobster and to cockle. Originally intended, as we suppose, to face the strong-toothed monsters of the Mediterranean, these foreigners have wandered northward to shores where their armour is not now needed;and yet centuries of idleness and security have not been able to persuade them to lay it by. This - if my explanation is the right one - is but one more case among hundreds in which peculiarities, useful doubtless to their original possessors, remain, though now useless, in their descendants. Just so does the tame ram inherit the now superfluous horns of his primeval wild ancestors, though he fights now - if he fights at all - not with his horns, but with his forehead.
Enough of Cardium tuberculatum. Now for the other animals of the heap; and first, for those long white razors. They, as well as the grey scimitars, are Solens, Razor-fish (Solen siliqua and S.
ensis), burrowers in the sand by that foot which protrudes from one end, nimble in escaping from the Torquay boys, whom you will see boring for them with a long iron screw, on the sands at low tide.
They are very good to eat, these razor-fish; at least, for those who so think them; and abound in millions upon all our sandy shores. Now for the tapering brown spires. They are Turritellae, snail-like animals (though the form of the shell is different), who crawl and browse by thousands on the beds of Zostera, or grass wrack, which you see thrown about on the beach, and which grows naturally in two or three fathoms water. Stay: here is one which is "more than itself." On its back is mounted a cluster of barnacles (Balanus Porcatus), of the same family as those which stud the tide-rocks in millions, scratching the legs of hapless bathers. Of them, I will speak presently; for I may have a still more curious member of the family to show you. But meanwhile, look at the mouth of the shell; a long grey worm protrudes from it, which is not the rightful inhabitant. He is dead long since, and his place has been occupied by one Sipunculus Bernhardi; a wight of low degree, who connects "radiate" with annulate forms - in plain English, sea-cucumbers (of which we shall see some soon) with sea-worms. But however low in the scale of comparative anatomy, he has wit enough to take care of himself; mean ugly little worm as he seems. For finding the mouth of the Turritella too big for him, he has plastered it up with sand and mud (Heaven alone knows how), just as a wry-neck plasters up a hole in an apple-tree when she intends to build therein, and has left only a round hole, out of which he can poke his proboscis. A curious thing is this proboscis, when seen through the magnifier. You perceive a ring of tentacles round the mouth, for picking up I know not what; and you will perceive, too, if you watch it, that when he draws it in, he turns mouth, tentacles and all, inwards, and so down into his stomach, just as if you were to turn the finger of a glove inward from the tip till it passed into the hand; and so performs, every time he eats, the clown's as yet ideal feat, of jumping down his own throat. So much have we seen on one little shell. But there is more to see close to it. Those yellow plants which I likened to squirrels'
