CHITIN (kī’-tĭn). A horny substance that forms the harder part of the outer covering of insects, lobsters, crabs, and the like.
CHLOROPHYLL (klō’-rō-fĭl). The green coloring matter of plants, which plays an essential part in the manufacture of starches and sugars by the leaves.
CILIUM (sĭl’-ĭ-ŭm). A minute, hairlike projection from a cell. Usually occurring in numbers wherever present, cilia set up a current by rhythmic lashing movements. Some one-celled animals and plants and some larvae of higher forms move by cilia.
COCKLE. A mollusk with a heart-shaped shell usually sculptured into radiating ridges and handsomely marked both inside and out. The cockle is a much more active shellfish than the related clams, and progresses along the bottom by surprising leaps and tumbles. These are effected by thrusting out a muscular “foot,” bending it under the shell, and suddenly straightening it.
CONGER EEL (kǒng’-gēr). Conger eels are exclusively marine, reach a weight of fifteen pounds or more in American waters and up to one hundred and twenty-five pounds in European, and are exceedingly voracious.
CONTINENTAL SHELF. The gently sloping bottom of the sea from the tide lines down to depths of approximately one hundred fathoms is known as the continental shelf. In places the continental shelf of the United States is about a hundred miles wide; in others, as off the Florida coast, it is only a few miles wide. Many parts of the present shelf were land in comparatively recent geological times. Most marine commercial fisheries are confined to waters over the shelf. The steeper descent from the edge of the shelf to the oceanic abyss is known as the continental slope.
COPEPOD (kō’-pē -pǒd). A large subclass of crustaceans (q.v.) all less than two-fifths of an inch long and most of them much smaller. Many are free-swimming members of the plankton; some use the bodies of living animals as homes from which they come and go without detriment to their host; others are parasites on the gills, skin, or flesh of fish. They are one of the most important links in the marine food chain, making plant foods available to the many young fishes and other creatures that feed on them. (See Calanus, for example.)
CRAB LARVA. Newly hatched crabs are transparent, big-headed creatures that bear no resemblance to their parents. As they grow they must shed the hard cuticle that covers them with an unyielding armor, and so they pass through a series of molts, each of which brings them a little closer to a crablike physique. Their early life is spent near the surface, swimming about actively and snapping up smaller creatures from the surrounding water.
CRANE FLY. An adult crane fly is a long-legged, mosquitolike insect often seen about streams at dusk, or flying about lights after dark. Their larvae live in the water or in moist places.
CROAKER. An abundant fish of the Atlantic Coast south of New England, which owes its common name to its ability to make a grunting or croaking sound by drumming with a pair of specialized muscles on its air bladder (a balloonlike sac under the backbone). This drumming may be heard a considerable distance under water. Another common name, used especially in the Chesapeake Bay area, is “hardhead.”
CROWBERRY. A low-growing evergreen shrub of Arctic regions from Alaska to Greenland, found also as far south as northern United States. Its berries are a favorite food of Arctic birds.
CRUSTACEAN. Animals that wear a segmented shell and have segmented legs are arthropods; arthropods that live in the water and breathe by gills are crustaceans. Familiar examples are lobsters, barnacles, shrimps, and crabs.
CTENOPHORE (tĕn’-o -fōr). A marine animal much like a jellyfish. Most ctenophores are cylindrical or pear-shaped and swim by the beating of hairlike cilia arranged in eight longitudinal bands or combs, hence the common name “comb jelly.” They are beautifully iridescent in sunlight and usually phosphorescent in darkness. They are important economically because they destroy large numbers of young fish.
CUNNER. A rather deep-bodied fish with long, spiny back fin, found especially about wharf piles and sea walls and sometimes offshore, from Labrador to New Jersey.
CURLEW. A large, long-billed bird belonging to the same general group as sandpipers. It ranges in winter to the Pacific Coast of South America, from which it migrates, either by way of the Pacific Coast or by Central America, Florida, and the Atlantic Coast, to the shores of the Arctic Ocean, where it breeds. The long-billed and Eskimo curlews were virtually exterminated during the past century, but fair numbers of the Hudsonian curlew remain.
CYANEA (sī-ā’-ne -å). This is the largest of the Atlantic Coast jellyfishes. In cold northern waters the bell-shaped body may be seven and one half feet across, with tentacles more than a hundred feet long. About ninety-five per cent of this great bulk is water. Common sizes are three to four feet across, with thirty- to forty-foot tentacles. Contact with the tentacles produces a severe burning sensation, because of the discharge of hundreds of minute “darts” from the stinging cells. In northern waters Cyanea is red, but the southern form may be a pale bluish or milky white.
DESMID (dĕs’-mǒd). A minute, one-celled, fresh-water alga, often beautifully shaped like a crescent, star, or triangle, and bright green in color.
DIATOMS (dī’-å-tǒm). One-celled algae in which the usual green coloring matter is masked by a yellow-brown pigment. The cell walls are impregnated with silica, and after death accumulate in bottom deposits, forming the basis of diatomaceous earth used in polishing powders. Beds of such earth, three hundred feet deep, have been discovered in the Rocky Mountains. Diatoms are the indispensable first links in aquatic food chains, making the nutrient minerals of the water available to the animals that eat them.
DOVEKIE (dŭv’-kĭ). A maritime bird a little smaller than a robin, belonging to the same family as the auks and puffins. They go ashore only to nest. At sea they are expert divers, and swim under water with their wings, instead of using their feet as the distantly related loons do.
DOWITCHER (dou’-ĭch-ēr). A medium-sized, long-billed shore bird of the sandpiper tribe, seen on the Atlantic Coast during migrations. It winters in Florida, the West Indies, and Brazil, and is believed to nest in northern Canada, east of Hudson Bay.
DRAGONFISH. In spite of its fierce appearance, only the small inhabitants of the deep sea need fear the dragon fish (called also “viperfish”), for it is only a foot long. Probably it spends its entire life in the dark regions that lie more than a thousand feet deep.
ECRET, SNOWY (ē’-grĕt). Often described as the “most dainty and graceful of the herons,” the snowy egret once was nearly exterminated because of unrestrained killing for the sake of the beautiful plumes it wears during the breeding season. This bird looks much like a young little-blue heron, but may be distinguished by its yellow feet.
EIDER. The eider is a true sea duck, and during its winter migration to the New England and Middle Atlantic Coast spends most of its time offshore, usually over the mussel beds from which it obtains its food by diving. This duck is the principal source of American eider down.
FATHOM. A nautical unit of measure equal to six feet.
FIDDLER CRAB. A small, gregarious crab of the beaches and salt marshes. In the male, one of the claws is greatly enlarged into a weapon for defense and attack. Possession of this “fiddle” is in one sense a disadvantage to the male, for it leaves him with only one claw to pick up food while the female has two. Fiddlers usually live in enormous colonies between the tide lines, each crab in its own small burrow.
FLUKE. A name often applied to the summer flounder (Paralichthys dentatus) in the Middle Atlantic and Chesapeake Bay area. This is one of the more active and predacious flounders, sometimes pursuing schools of fish to the surface. It has a chameleonlike ability to match the color of its background. Average-sized flukes are two feet long.
FORAMINIFERA (fō-răm’-ĭ-nĭf’-ēr-å). A group of one-celled animals usually having limy shells with numerous pores or openings through which long processes of the living substance or protoplasm stream out. The effect is extremely beautiful. After death the shells of
these minute creatures sink to the bottom and form chalk beds or deposits of limestone which may be a thousand feet thick. The pyramids of Egypt are built of enormous blocks of limestone formed by fossil Foraminifera.
FRUSTULE. The shell of a diatom, which is in two overlapping parts, like a box and its lid. Being almost pure silica, it is nearly indestructible. The shells are varied in shape and are delicately marked in a great diversity of patterns. These markings are sometimes used to test the power of microscope lenses.
FULMAR (fŭŭl’-mår). A bird of the open ocean, belonging to the same family as the petrels and shearwaters. It is a little smaller than a herring gull, spends much of its time on the wing, and is especially active in stormy weather. Its summer range includes Greenland, Davis Strait, and Baffin Bay, while its principal winter resort is off the American coast, especially on the Grand Banks and Georges Bank.
GANNET. On this side of the Atlantic, gannets nest only on rocky cliffs of the Gulf of St. Lawrence, and winter from North Carolina to the Gulf of Mexico. They are large, white birds of the open sea and obtain their food by diving with great force, often from a height of more than a hundred feet. Sometimes a flock of several hundred will attack a school of herring or mackerel.
GHOST CRAB. A large crab, so pale as to be nearly invisible against the sandy beaches where it lives. It is found from New Jersey to Brazil, and is a common inhabitant of our southern beaches. It is very wary and can outdistance a swift runner. Although it does not hesitate to enter the water when necessary, it lives above the tide line in burrows about three feet deep.
GILL NET. A gill net may be anchored on the bottom or buoyed at the top or at almost any intermediate depth, but in any event its position in the water is much like that of a tennis net. Fish are caught in gill nets by thrusting their heads through the meshes and becoming caught by the gill covers, which project slightly, like flaps. A drift gill net is weighted so that it sinks to the bottom and drifts along with the tide.
GILL RAKER. In breathing, a fish takes in water through the mouth and expels it through the gill openings, which are flanked by the delicate gill filaments that absorb oxygen. The gill rakers are bony projections at the inner entrances to the gill openings. Their function is to strain the food organisms out of the water and also to protect the gill filaments from injury. They have been compared to the human epiglottis, which keeps food from getting into the windpipe.
GLASSWORM, also called ARROWWORM or SAGITTA (sa-jĭt’-a). These are small, elongated, and transparent worms that live only in the sea and are found from the surface to great depths. They are fierce and active predators, and eat large numbers of young fish.
GREBE. Grebes on the water bear a general resemblance to ducks, but if startled will dive rather than fly. They are able to swim considerable distances under water and not uncommonly are caught in fishermen’s nets. Usually found in lakes, ponds, bays, and sounds, some grebes venture out to sea for fifty miles or more.
GYRFALCON (jûr’-fôl-kŭn). A large, predominantly white Arctic falcon that lives chiefly on small birds and lemmings. Occasionally it may wander south in winter to New England, New York, and northern Pennsylvania.
HADDOCK. A fish of the cod family which lives almost exclusively on the bottom at practically all depths over the continental shelf. The largest haddock on record was thirty-seven inches long and weighed twenty-four and one half pounds.
HAKE. Like the haddock, the hakes are members of the cod family, although not at all codlike in appearance, being more slender and tapering fishes. A characteristic feature is the long and feelerlike ventral fin, with which the fish is believed to detect the presence of prey on the bottom.
HATCHETFISH. A compressed, silvery, deep-sea fish with highly developed light organs.
HERMIT CRAB. These curious crabs live within the shells of snail-like mollusks, dragging this “house” about with them as protection for their delicate abdomens, which are covered only by a thin skin. When a hermit crab grows too large for its house it must seek a new one, and the inspection of possible quarters is made with great care. Once the selection has been made, the crab whips out of the old shell and into the new with remarkable celerity. Allegedly, it does not confine itself to empty shells, but may forcibly remove the rightful owner.
HOLDFAST. A rootlike structure, as of algae and other simple plants, for attachment to the substratum.
HOOK-EARED SCULPIN. A curious fish with fanlike pectoral fins and conspicuous hooks on the cheeks. It is a coldwater fish, found from Labrador south to Cape Cod and Georges Bank.
HYDROID (hī’-droid). A plantlike animal of the jellyfish group, that is attached at one end and usually has a mouth surrounded by tentacles at the other. The resemblance to a many-branched plant is especially strong when hydroid forms occur in colonies, with a central stalk serving to transport food to the various members.
JAEGER (yā’-gēr). The jaegers belong to the same order of birds as gulls and terns, but in their habits they resemble falcons and other birds of prey. On the high seas, where they winter, they play the part of pirates, forcing gulls, shearwaters, and other birds to give up their booty. During their nesting season on the Arctic tundras, they prey on small birds and lemmings.
JINGLE SHELL. A small mollusk with a very thin shell, usually of a lustrous golden, lemon, or peach color. The empty shells accumulate in windrows on the beach and are said to produce a ringing or jingling sound when disturbed by wind or tide. Jingles are found from the West Indies to Cape Cod.
KILLIFISH. Small minnows of schooling habit, found in droves of thousands of individuals in shallow bays, coves, and marshy places along the coast.
KITTIWAKE. The kittiwake is a small gull, one of the hardiest of the tribe, for it is truly an oceanic bird and seldom is seen inland except during migrations. This is the gull that follows transatlantic liners for long distances.
KNOT. A somewhat robinlike bird of the shore, arriving in the United States from South America in early April. Its nesting grounds were long unknown, but have now been found in the wildest and most remote parts of Grinnell Land, Greenland, and Victoria Land.
LATERAL LINE. The lateral line may be seen in most fishes as a row of pores extending along the flanks from the gill covers to the tail. Internally, these pores communicate with a long, mucous-filled tube which, in turn, is connected with many sensory nerves. The lateral-line organ is believed to allow the fish to detect sound vibrations of a frequency so low that they would scarcely be audible to the human ear. In practice, this means that a fish can sense at a distance the approach of another fish; or can tell that it is coming near to an obstacle, as a wall of rock. According to recent experiments, the lateral line may also help the fish to detect changes in the temperature of the water.
LAUNCE. A slender, round-bodied fish, in appearance something like a small eel. Between the tide lines, it buries itself in the sand while the tide is out. It is a plentiful fish along sandy beaches from Cape Hatteras to Labrador and is abundant over the shoaler parts of the offshore banks. Like most other small, schooling fishes, it forms the food of many ocean predators, including finback whales.
LEMMING (lĕm’-ing). A small, mouselike rodent chiefly of Arctic regions, with very short tail, small ears, and furry feet. The Lapland lemmings are remarkable for the mass migrations which they periodically undertake. At such times they advance in great bands in the chosen direction, heedless of obstacles in their path. When they come to the sea they rush into it and are drowned.
LINE TRAWL. Line trawling is an old-fashioned method of fishing for groundfish which has not been wholly superseded by the modern diesel-engined otter trawler. In line trawling, each vessel carries dories, from which the gear is set. A trawl line consists of a long ground line to which short baited lines are attached at intervals of about five feet. Each end of the long line is anchored and marked with a buoy. At intervals, the fishermen take up the lines and remove the fish. Sometimes (in “underrunning” the trawl) the line is merely passe
d across the dory, the fish removed, the hooks rebaited, and returned at once to the water.
LONGSPUR, LAPLAND. A bird of the finch and sparrow tribe, about the size of a song sparrow. In winter, longspurs are occasionally to be seen in northern United States and southern Canada, but summer finds them on nesting grounds beyond the tree line in northern Canada and in Greenland and scattered Arctic islands. On the western plains they are described as occurring in “long straggling flocks, all singing together.”
LOOKDOWN FISH. A very curious fish common from Chesapeake Bay southward. Its body is high and compressed from side to side, and is a beautiful silvery color with opalescent lights. The long, straight profile and high “forehead” give a distinct impression that the fish is looking down its nose.
MARSH SAMPHIRE (săm’-fīr). The marsh samphire or glasswort is a plant of the salt marshes that turns a vivid red in autumn, forming patches of brilliant color.
MARSH TREADER. A long and slender-bodied water insect that walks about deliberately over the leaves of water lilies or on the surface film, watching for the mosquito larvae, water boatmen, and small crustaceans on which it preys.
MAY FLY. The greater part of the life of a May fly is spent in the immature stage which lives in clean, fresh water as long as three years, burrowing into banks and under stones or running about over the bottom. At maturity it emerges, mates, lays its eggs, and dies, all within one or two days. The life of the adult May fly has become a symbol of a brief and ephemeral existence.
MEDUSA. The familiar jellyfish in the shape of a bell, umbrella, or disc is known as a medusa. Some jellyfishes have alternating medusa and hydroid stages in their life history. (See hydroid.)
MENHADEN (mĕn-hā’-d’n). A schooling fish closely related to shad and herring, found from Nova Scotia to Brazil. It is caught in large quantities for the preparation of oil, meals for stock feeding, and fertilizer, but is not a food fish. It has been described as the prey of every larger predacious animal that swims, including whales, porpoises, tuna, swordfish, pollock, and cod.