INTERESTING SEA DWELLERS

Lake Wakatip Mail, Issue 4325, 3 August 1937, Page 7

INTERESTING SEA DWELLERS

CURIOSITIES OF NATURAL HISTORY The sponge is, perhaps, one of the most curious of fishes, for fish it is, although several eminent naturalists of the past maintained that it is not. One naturalist says that the animalcule of the sponge is a stomach without arms, very simple, very elementary—in short, an animal all stomach! The innumerable canals in the sponge are at once its digestive organs and breathing pores. If a sponge is broken it will be seen that the pores are of two different sizes. In the living state the water containing the particles of food is constantly being absorbed by the small holes, and is discharged by the larger, the food being retained. The number of species of sponges is very large. The red and green colouring matter found in ponds as well as the sea is often caused by the presence of millions of animals called infusoria. They are found everywhere. Their remains are found on the tops of the highest mountains, and they are found alive in the greatest depths of the sea. They are invisible to the eye, their mean size being only one-six-teenth part of an inch. Though generally colourless, they are sometimes red, green, blue, and brown. Seen under a microscope they appear oblong, transparent bodies, sometimes covered by hairs, which enable them to move. Though so small, they can lose part of their bodies without apparently suffering inconvenience. When one part of the body becomes old it dies, the dead part drops off, and the animal thus reduced swims about as though nothing has happened. The hydra, an animal which has the power of turning itself inside out, is often found in ponds as well as the sea. Ju appearance the hydra looks like a piece of weed, sometimes of a red and sometimes of a green colour. It consists of a small coloured sac closed at one end and open at the other, and bearing round the opening which serves the purpose of a mouth a number of coloured tentacles. The hydne have no lungs, no liver, no intestines, no nervous system, no heart. The tentacles are holloiv and communicate with the mouth. The hydra can be turned inside out, like a glove, without injury to the animal, which, a day or two afterwards, resumes its usual functions. What was once the outer service, is now performing the duties of a stomach, digesting the food, while what was the stomach now does duty for a skin; but after a time the animal returns to its original condition. If a hydra is cut into a number of pieces, each piece will grow into an entire animal, so that if a hydra wants to procure for itself the blessings ot a family, all that it has to do is to cut off one or two arms, and each piece will soon be a new individual, in all respects like its parent. Imagine a mass of fine seaweed, of a brilliant vermillion colour, floating on the water, and you have a 'fair idea of the Agalma rubra. This animal consists ot a long, hollow tube, the length of which may be three feet, and the breadth an eighth of an inch, beneath which are a number of swimming bladders. The hinder portion of the animal is covered by long hairs, which constitute a formidable stinging apparatus. Another curious animal is the medusa. If we take one in our hands, the natural heat is sufficient to dissolve it into water. Looking more like a mushroom than anything else, it is often of a pale blue or rose colour. The tissue of a medusa is “so fragile that when abandoned by the waves on the beach it melts and disappears, without leaving a trace of its ever having existed.” Found principally in the Arctic Seas, they constitute one of the chief supports of the whale. An anemone can be cut into any number of parts. Each part will develop into a perfect animal, and the part cut off will be quickly replaced. The size of the prey on which the anemone feeds is often of equal bulk to the animal. A doctor had taken to him an anemone about 2in in diameter, which had managed to swallow a shellfish of the size of an ordinary saucer. “ The shell-fish was fixed in the stomach of the animal so as to divide it into two parts, and the animal had become thin and flattened like a pancake. All communication between the interior portion of the stomach and the mouth was, of course, prevented. Instead of dying, the animal availed itself of the accident to increase its enjoyment. A new mouth grew on what had been the base, and led to the stomach, and the animal became a sort of Siamese twin, but with greater intimacy ana extent in its union! ” The starfish is also a curious animal. Its mouth is directly in the centre, and almost immediately under it is the stomach, while the digestive organs are in its arms. Starfish eat oysters, but naturalists differ as to the precise way in which they devour them. Ancient naturalists believed that the starfish waited for a moment when the oyster opened its valves to introduce one of its rays into the opening, and having put one foot into the domicile it soon put the other four feet in and finished up by devouring the native. Some naturalists assert that, obtaining possession of the oyster, the starfish places its mouth at the edge of the shell, and then with the assistance of a fluid, which its mouth secretes, it forces open the valves, and the entrance is obtained. Another naturalist explains that the oyster is seized by the starfish and held tight by its mouth; the starfish hen everts its stomach and envelopes the oyster, which forces it to open its shell. The holothuria is called “ sea-cucum-ber,” from its resemblance to a cucumber. When it is attacked by an enemy it does not stand up and fight, but by a sudden movement, it ejects its teeth, stomach, digestive apparatus, and nearly all its intestines, and then shrivels its body to almost nothing. When the danger is past, the animal commences to’replace the organs.