since it breathes through the skin, and it has sufficient knowledge of soil texture and plasticity to recognize the futility of attempts at burrow building with unmanageable, large grains of sand. These creatures are nocturnal, rarely appearing by day unless "drowned out" of the burrows. During the day they lie near the surface extended at full length, the head uppermost. Here they are discovered by keeneyed birds and sacrificed by thousands, notwithstanding the strong muscular protest of which they are capable. Seemingly conscious of its inability to find the way back to its home, an earthworm anchors tight by its tail while stretching its elastic length in a foraging expedition. It is an omnivorous creature, including in its diet earth, leaves, flowers, raw meat, fat, and even showing cannibalistic designs on fellow earthworms. In the schoolroom, earthworms may be fed on pieces of lettuce or cabbage leaves. A feeding worm will show the proboscis, an extension of the upper lip used to push food into the mouth. The earthworm has no hard jaws or teeth, yet it eats through the hardest soil. Inside the mouth opening is a very muscular pharynx, which can be extended or withdrawn. Applied to the surface of any small object it acts as a suction pump, drawing food into the food tube. The earth taken in furnishes some organic matter for food; calcareous matter is added to the remainder before being voided. This process is unique among animals. The calcareous matter is supposed to be derived from leaves which the worms eat. Generally the earth is swallowed at some distance below the surface, and finally ejected in characteristic "castings. Thus, the soil is slowly worked over and kept in good condition by earthworms, of which Darwin says: "It may be doubted whether there are many other animals which have played so important a part in the history of the world as have these lowly organized creatures." References-The Earthworm, Darwin; The Natural History of Some Common Animals, Latter. "Fly fishing is an art, a fine art beyond a doubt, but it is an art and, like all art, it is artificial. Fishing with an angleworm is natural. It fits into the need of the occasion. It fits in with the spirit of the boy. It is not by chance that the angleworm, earthworm, fishworm, is found in every damp bank, in every handy bit of sod, the green earth over, where there are races whose boys are real boys with energy enough to catch a fish. It is not by chance that the angleworm makes a perfect fit on a hook, with no anatomy with which to feel pains, and no arms or legs to be broken off or to be waved helplessly in the air. Its skin is tough enough so as not to tear, not so tough as to receive unseemly bruises, when the boy is placing it on the hook. The angleworm is perfectly at home on the hook. It is not quite comfortable anywhere else. It crawls about on sidewalks after rain, ached and emaciated. It is never quite at ease even in the ground, but on the hook it rests peacefully, with the apparent feeling that its natural mission is performed.” -"BOYS' FISH AND BOYS' FISHING," BY DAVID STARR JORDAN. LESSON CVII THE EARTHWORM Leading thought-The earthworm is a creature of the soil and is of much economic importance. Method-Any garden furnishes abundant material for the study of earthworms. They are nocturnal workers and may be observed by lan tern light. To form some estimate of the work done in a single night, remove the "casts" from a square yard of earth one day, and examine that piece of earth the next. It is well to have a terrarium in the schoolroom for frequent observation. Scatter grass or dead leaves on top of the soil, and note what happens. For the study of the individual worm and its movements, each pupil should have a worm with some earth upon his desk. Observations-1. How does the earthworm crawl? How does it turn over? Has it legs? Compare its movement with that of a snake, another legless animal. What special provision for locomotion has the earthworm? Compare the lengths of the contracted and extended body. How accounted for? Describe the body-its shape and color, above and below. Examine the segments. Do all the worms have the same number? Compare the head end with the tail end of the body. Has every worm a "saddle," or clitellum? 4. Does the earthworm hear easily? Has it eyes? Is it sensible to smell or to touch? What sense is most strongly developed? 5. Describe the home of the earthworm. Is it occupied by more than one worm? How long does it take a worm to make a burrow? How does it protect its home? How does it make a burrow? In what kind of soil do you find earthworms at work? 6. Is the earthworm seen most often at night or by day? Where is it the rest of the time? How does it hold to its burrow? When is the tail end at the top? When the head end? 7. What is the food of the earthworm? How does it get its food? 8. Look for the eggs of the earthworm about manure piles or under stones. 9. What are the enemies of the earthworm? Is it a friend or an enemy to us? Why? IO. The earthworm is a good agriculturist. Why? THE CRAYFISH Teacher's Story HEN I look at a crayfish I envy it, so rich is it in organs with which to do all that it has to do. From the head to the tail, it is crowded with a large assortment of executive appendages. In this day of multiplicity of duties, if we poor human creatures only had the crayfish's capabilities, then might we hope to achieve what lies before us. The most striking thing in the appearance of the crayfish is the great pair of nippers on each of the front legs. Wonderfully are its "thumb and finger" put together; the "thumb" is jointed so that it can move back and forth freely; and both are armed, along the inside edge, with saw teeth and with a sharp claw at the tip so that they can get a firm grip upon an object. Five segments in these great legs can be easily seen; that joining the body is small, but each successive one is wider and larger, to the great forceps at the end. The two stout segments behind the nippers give strength, and also a suppleness that enables the claws to be bent in any direction. The legs of the pair behind the big nippers have five segments readily visible; but these legs are slender and the nippers at the end are small; the third pair of legs is armed like the second pair; but the fourth and fifth pairs lack the pincers, and end in a single claw. But the tale of the crayfish's legs is by no means told; for between and above the great pincers is a pair of short, small legs tipped with single claws, and fringed on their inner edges. These are the maxillapeds, or jaw-feet; and behind them, but too close to be seen easily, are two more pairs of jaw-feet. As all of these jaw-feet assist at meals, the crayfish apparently always has a "three fork" dinner; and as if to provide accommodations for so many eating utensils, it has three pairs of jaws all working sidewise, one behind the other. Two of these pairs are maxillæ and one, mandibles. The mandibles are the only ones we see as we look in between the jaw-feet; they are notched along the biting edge. Connected with the maxillæ, on each side, are two pairs of threadlike flappers, that wave back and forth vigorously and have to do with setting up currents of water over the gills. Thus we see that, in all, the crayfish has three pairs of jaw-feet, one pair of great nippers and four pairs of walking feet, two of which also have nippers and are used for digging and carrying. When we look upon the crayfish from above, we see that the head and thorax are fastened solidly together, making what is called a cephalothorax. The cephalothorax is covered with a shell called the carapace, which is the name given also to the upper part of the turtle's shell. The suture where the head joins the thorax is quite evident. In looking at the head, the eyes first attract our attention; each is black and oval and placed on the tip of a stalk, so it can be extended or retracted or pushed in any direction, to look for danger. These eyes are like the compound eyes of insects, in that they are made up of many small eyes, set together in a honeycomb pattern. The long antennæ are as flexible as braided whiplashes, large at the base and ending in a threadlike tip. They are composed of many segments, the basal ones being quite large. Above the antennæ on each side, is a pair of shorter ones called antennules, which come from the same basal segment; the lower one is the more slender and is usually directed forward; the upper one is stouter, curves upward, and is kept always moving, as if it were constantly on the alert for impressions. The antennæ are used for exploring far ahead or behind the creature, and are often thrust down into the mud and gravel at the bottom of the aquarium, as if probing for treasure. The antennules seem to give warning of things closer at hand. Between the antennæ and antennules is a pair of fingerlike organs, that are hinged at the outer ends and can be lifted back, if we do it carefully. In looking down upon a crayfish, we can see six abdominal segments and the flaring tail at the end, which is really another segment greatly modified. The first segment, or that next to the cephalothorax, is narrow; the others are about equal in size, each graceful in shape, with a widened part at each side which extends down along the sides of the creature. These segments are well hinged together so that the abdomen may be completely curled beneath the cephalothorax. The plates along the sides are edged with fringe. The tail consists of five parts, one semicircular in the center, and two fan-shaped pieces at each side, and all are margined with fringe. This tail is a remarkable organ. It can be closed or extended sidewise like a fan; it can be lifted up or curled beneath. Looking at the crayfish from below, we see on the abdomen some very beautiful featherlike organs called swimmerets. Each swimmeret consists of a basal segment with twin paddles joined to its tip, each paddle being narrow and long and fringed with hairs. The mother crayfish has four pairs of these, one pair on each of the second, third, fourth and fifth segments; her mate has an additional larger pair on the first segment. These swimmerets, when at rest, lie close to the abdomen and are directed forward and slightly inward. When in motion, they paddle with a backward, rhythmic motion, the first pair setting the stroke and the other pairs following in succession. This motion sends the body forward, and the swimmerets are chiefly used to aid the legs in forward locomotion. A crayfish, on the bottom of a pond, seems to glide about with great ease; but place it on land, and it is an awkward walker. The reason for this difference lies, I believe, in the aid given by the swimmerets when the creature is in water. Latter says: "In walking, the first three pairs of legs pull and the fourth pair pushes. Their order of movement is as follows: The first on the right and the third on the left side move together, next the third right and the first left, then the second right and fourth left, and lastly the fourth right and second left." When the crayfish really wishes to swim, the tail is suddenly brought into use; it is thrust out backward, lays hold of the water by spreading out widely, and then doubles under with a spasmodic jerk which pulls the creature swiftly backward. The crayfish's appearance is magically transformed when it begins to swim; it is no longer a creature of sprawling awkward legs and great clumsy nippers; now, its many legs lie side by side supinely and the great claws are limp and flow along in graceful lines after the body, all obedient to the force which sends the creature flying through the water. I cannot discover that the swimmerets help in this movement. The mother crayfish has another use for her swimmerets; in the spring, when she is ready to lay eggs, she cleans off her paddles with her hind legs, covers them with waterproof glue, and then plasters her eggs on them in grapelike clusters of little dark globules. What a nice way to look after her family! The little ones hatch, but remain clinging to the maternal swimmerets, until they are large enough to scuttle around on the brook bottom and look out for themselves. The breathing apparatus of the crayfish cannot be seen without dissection. All the walking legs, except the last pair, have gills attached to that portion of them which joins the body, and which lies hidden underneath the sides of the carapace or shell. The blood is forced into these gills, sends off its impurities through their thin walls and takes in the oxygen from the water, currents of which are kept steadily flowing forward. Crayfishes haunt still pools along brooksides and river margins and the shallow ponds of our fresh waters. There they hide beneath sticks and stones, or in caves of their own making, the doors of which they guard with the big and threatening nippers, which stand ready to grapple with anybody that comes to inquire if the folks are at home. The upper surface of the crayfish's body is always so nearly the color of the brook bottom, that the eye seldom detects the creature until it moves; and if some enemy surprises one, it swims off with terrific jerks which roil all the water around and thus covers its retreat. In the winter, our brook forms hibernate in the muddy bottoms of their summer haunts. There are many species; some in our Southern States, when the dry season comes on, live in little wells which they dig deep enough to reach water. They heap |