Fig. 4.—British Marine Worms or Chætopods.
a, Arenicola piscatorum. Lug-worm largely used for bait by sea-fishermen. It burrows in sea-sand and clay as the earth-worm does in soil. Half the natural size, linear.
b, Nephthys margaritacea, actively swimming. It also burrows in the sea-sand. Natural size.
c, Eunice sanguinea, a very handsome marine worm (often used for bait) which lives in clefts in the submarine rocks and also swims actively. The numerous filaments on the sides of the ringed body are the gills of a rich blood-colour. The figure is one-third of the natural size, linear.
The shrimper will probably catch also some very young fish fry—including young flat-fish about 2 inches long. If he explores the exposed surface of sand near the low-tide limit, he will find a variety of indications of burrowing animals hidden beneath. Little coiled masses like the "castings" of earth-worms are very abundant in places, and are produced by the fisherman's sand-worm, or "lug-worm" ([Fig. 4, a]). A vigorous digging to the depth of a foot or two will reveal the worm itself, which is worth bringing home in a jar of sea-water in order to see the beautiful tufts of branched gills on the sides of the body, which expand and contract with the flow of bright red blood showing through their delicate walls. Other sand-worms, from 2 to 6 inches long, will at the same time be turned up,—worms which have some hundred or more pairs of vibrating legs, or paddles, arranged down the sides of the body, and swim with a most graceful, serpentine curving of the mobile body ([Fig. 4, b]). These sea-worms are but little known to most people, although they are amongst the most beautifully coloured and graceful of marine animals. Hundreds of different kinds have been distinguished and described and pictured in their natural colours. Each leg is provided with a bundle of bristles of remarkable shapes, resembling, when seen under a microscope, the serrated spears of South Sea Islanders and mediaeval warriors. These worms usually have (like the common earth-worm) red blood and delicate networks of blood-vessels and gills ([Fig. 4, c]), whilst the head is often provided with eyes and feelers. They possess a brain and a nerve-cord like our spinal cord, and from the mouth many of them can suddenly protrude an unexpected muscular proboscis armed with sharp, horny jaws, the bite of which is not to be despised. These "bristle-worms," or "chætopods," as they are termed by zoologists, are well worth bringing home and observing in a shallow basin holding some clean sea-water.
At many spots on our coast (e.g. Sandown, in the Isle of Wight, and the Channel Islands) rapid digging in the sand at the lowest tides will result in the capture of sand-eels, a bigger and a smaller kind, from 1 foot to 6 inches in length. These are eel-shaped, silvery fish, which swim near the shore, but burrow into the soft sand as the tide recedes. They are excellent eating. We used at Sandown to make up a party of young people to dig the smaller "sand-eels," or "sand-launce." The agility and rapid disappearance of the burrowing fish into the sand when one thought one had safely dug them out, rendered the pursuit difficult and exciting. Then a wood fire on the beach, a frying-pan, fat, flour, and salt were brought into operation, and the sand-eels were cooked to perfection and eaten.
Fig. 5.—The shell of the
Heart-urchin (Spatangus
purpureus) with its
spines rubbed off.
One-fourth the actual
diameter.
Some of the marks or small heaps of sand on the flats exposed at low tide are characteristic of certain shell-fish. The "razor-fish" [(Fig. 19, b)]—a very much elongated clam, or mussel, with astonishing powers of rapid burrowing—leaves a hole on the surface like a keyhole, about an inch long. It can be dug up by an energetic spadesman, but a spoonful of common salt poured over the opening of its burrow will cause it to suddenly shoot out on to the surface, when it may be picked up, and the hunter spared any violent exertion. The curious heart-urchin ([Fig. 5]), as fragile as an egg-shell, and covered with long, closely-set spines like a brush, is often to be found burrowing in the sand, as well as the transparent, pink-coloured worm known as Synapta, in the skin of which are set thousands of minute calcareous anchors hinged to little sculptured plates. These burrowers swallow the sand and extract nutriment from stray organic particles mixed in it.
The mere sand-flat of the low tide is not a bad hunting ground; but the rock pools, often exposed when the tide is out, and the fissures in the rocks and the under surfaces of slabs of rock revealed by turning them over—are the greatest sources of varied delight to the sea-shore naturalist. It is well to take a man with you on to these rocks to carry your collecting bottles and cans, and to turn over for you the larger slabs of loose stone, weighing as much as a couple of hundredweight. The most striking and beautiful objects in these rock pools are the sea-anemones ([Fig. 6] and [Frontispiece]). They present themselves as disk-like flowers from 1 to 5 inches in diameter, with narrow-pointed petals of every variety of colour, set in a circle around a coloured centre. The petals are really hollow tentacles distended with sea-water, and when anything falls on to them or touches them they contract and draw together towards the centre. The centre has a transverse opening in it which is the mouth, and leads into a large, soft-walled stomach, separated by its own wall from a second spacious cavity lying between that wall and the body wall, and sending a prolongation into each tentacle. The stomach opens freely at its deep end into this second "surrounding" chamber, which is divided by radiating cross walls into smaller partitions, one corresponding to each tentacle. The nourishing results of digestion, and not the food itself, pass from the stomach into the subdivided or "septate" second chamber. There is thus only one cavity in the animal, separable into a central and a surrounding portion.