The whole high-water line is strewn with the blanched and parted valves of the Beach Clam. Here and there yellowish streaks appear upon the gray sand, formed by the detritus of submarine shells. Among the fragments are often found perfect specimens, some of them with the living animal.
We can examine them as we go back, but now let us cross the "Creek." It is a creek only by courtesy or an Americanism, at the present day; but when those miles of fertile fields upon the north were unreclaimed, the dank herbage hindered evaporation, and Easton's Pond was fed by unfailing streams. Then the vast body of overflowing water swept a deep channel, which the sea, rolling far up towards the pond, widened and made permanent. Boats came from ships in the offing, and followed its course to "Green End," with no fear of grounding; and traditionary pirates there bestowed in secret caves their ill-gotten gains.
Now, the Creek is a mere streamlet, and the flow of the tide is restricted to its mouth. With our rubbers we may ford it dry-shod; but if you choose to cross the bridge, we must wade through shifting sand, and our walk will be the longer. In midsummer the bed is dry, and almost obliterated by the drift. On the approach of autumnal rains, the farmers plough a passage for the water, to prevent their lands from being submerged.
On the east side, masses of conglomerate rock are strewn in wild confusion. By the action of untold ages the connecting cement is worn away from between the pebbles, leaving them prominent; and wherever the attrition of the sea has loosened one from its bed, the hollow has become the habitation of Mollusca and Algae.
Beyond that ponderous boulder are many dark recesses among the overlying stones. Strip back your sleeve, thrust in your hand, and grope carefully about. In this way I once grasped a prickly thing that startled me. Drawing it to light, it proved to be an Echinus, Sea-Urchin, or Sea-Egg. That one was not larger than a walnut, was shaped like a brioche, and resembled a chestnut-burr. Its color was a delicate green, verging to brown.
Much larger living Echini are found on this spot. There is a shell now, more than two inches in diameter. It is wholly covered with spines half an inch in length. Radiating from a common centre, flexible at the base, they stand erect at right angles with the shell when the Urchin is in health; but in disease or death order is lost, and they lie across each other in great confusion. Their connection with the shell is very remarkable, for it is by a ball-and-socket joint,—the same articulation which gives the human hip its marvellous liberty of action. Between them are five rows of minute holes, and, in life, a transparent, hair-like foot is protruded from each, at the pleasure of the owner. When disposed to change its situation, it stretches forth those on the side towards which it would go, fixes them by means of the sucker at the tip of each, and, simultaneously withdrawing those in the rear, pulls itself along.
The mouth, placed in the centre of the base, is very large in proportion to the size of the animal. It is formed of five shelly, wedge-shaped pieces, each ending in a hard, triangular tooth. The whole mouth is a conical box, called by naturalists "Aristotle's lantern."
The shell is hardly thicker than that of a hen's egg, and is even more fragile. When the spines are rubbed off, the brioche-like shape is modified, and in place of the depression in the middle of the upper side there is seen a slight prominence.
Mine was a very inoffensive creature. He occupied the same corner for many weeks, and changed his place only when a different arrangement of stones was made. He then wandered to a remote part of the tank and chose a new abode. Both retreats were on the shady side of a stone overhung with plants. There for months he quietly kept house, only going up and down his hand-breadth of room once or twice a day. Minding his own business without hurt to his neighbor, he dwelt in unambitious tranquillity. Had he not fallen a victim to the most cruel maltreatment, he might still adorn his humble station.
As he was sitting one evening at the door of his house, bending about his lithe arms in the way he was wont, two itinerant Sticklebacks chanced to pass that way. They paused, and, not seeing the necessity for organs of which they had never known the use, they at once decided on their removal.