Home › The Sciences › Reptiles, or Amphibia: Zoophytes

Reptiles, or Amphibia: Zoophytes

Zoophytes and Infusoria. Though ranged under one head, yet Zoophytes are the lowest kind of animation, and Infusoria, often the highest in activity, and apparent intelligence. Our knowledge of both is recent. Two centuries ago, naturalists did not ascribe sensation to the beings called zoophytes, and the microscope had not facilitated our penetration into a part of the creation, till then invisible, though not less wonderful and various than the visible. There are forty species of animal anemones or actiniæ. They are beautiful in structure, and wonderful in their economy. They are of a cylindrical figure, or pear or funnel-shaped, but often like a marigold or rose. They are found firmly fixed on the rocks washed by the sea. They swell or contract at pleasure. They devour fish, crabs, etc., as well as flesh. They spread their numerous arms, or tentacula, and if one seizes any prey, the rest unite in securing it, and carrying it to the mouth. They are hermaphrodite, and cast their young from their mouth; and they often divide and become two animals, and also if cut into several parts; while, if torn away the very shreds become perfect actiniæ. They cannot live in fresh water. They have sensitive feelings, shrink in case of danger, and enjoy the light, but no eyes have been traced. They can float in the sea. The zoophytes which produce coral reefs are of the genera Meandrina, Caryphyllia, and Astrea. The reefs are curvilinear, with a lagoon in the centre, which gradually fills up the younger and smaller zoophytes being in the inner circle. They raise it to the level of low water, and then stop. Fragments raised from the deep raise the wall above highwater. Tides and currents carry it to trunks of trees, herbage, etc., and it soon becomes the resort of birds.

INFUSORIA, so little contemplated, were raised by Ehrenberg into scientific estimation. He fed them with agreeable colored substances; and hence, discovered their masticatory organs, their stomach and stomachs, their intestinal canal, their generative organs, muscles, nerves. They propagate so rapidly, that he calculated the hydatina senta might, in 20 days, become a million, and in twenty-four days 17 millions. Some divide themselves, and so multiply rapidly, They see, for they move with precision and purpose; and they think, for they avoid danger, and display artifices. In fact, they have all the appendages of larger insects, and often some peculiar to themselves, but difficult to understand. They are produced by mixture of various substances in fluids; and by some supposed to be spontaneous generations, while others have referred their origin to various causes. Hempseed, rice, lentils, peas, pepper, beet-root, blighted corn, etc., all yield various kinds on being macerated in water; and, however much boiled, the smaller kinds appear. Vinegar, too, produces eels; and all animals substances in putrescence display them. There are none in fresh rain-water, or pure spring-water. Sea-water produces them in swarms. If paste made with flour and water is suffered to go sour, without becoming mouldy, the surface will soon be found covered with an infinite number of minute living beings, which, from their general similarity to that animal, have been called eels. The same animals, or, as some authors think, a different species, is found in bad vinegar, and other mild acids. These animals are viviparous, and their increase is astonishing, for a hundred or more have been seen to issue from one of them. Lewenhoeck saw hundreds of animalculæ in the space of a grain of sand, and he says ten thousand organized beings. A drop of water contains hundreds, all in extreme activity, swimming or crawling with freedom and purpose. They appear to subsist on the atoms of the infusion, or they prey on others. Some have the forms of flying dragons with all their parts, others are like polype, some like worms, others with many legs like insects, while others have machinery of wheels which turn, creating vortexes which enable them to collect food. Some are like plants, with branches, each terminated with animalculæ, and the trunk and branches alternately draw in and spread. Other are like hydatids, and evolve their generations from the skin; and all hermaphrodites.

MAMMALIA.

Mammalia are vertebrated organizations, with lungs for breathing, warm red blood, a heart with two ventricles and two auricles, a diaphragm, teats or mammæ, for giving milk, hairy or smooth skin, and viviparous. The cervical vertebræ are seven, attached before to a sternum, with cartilages, and commencing from the suspended shoulder-blade. To these are annexed the humerus, or upper arm, with a forearm consisting of a radius and cubitus, finished by a hand of metacarpic bones and fingers; or by phalanges with nails or hoofs. The hinder or posterior extremities are attached to the spine, so as to form a girdle or pelvis, which again is divided into the ilium attached to the spine, next it the pubis, and behind it the ischum. Their point of union is the articulation or junction of the femur or thigh, connected with the leg compound or two bones, the tibia or skin, and the fibula. The foot resembles the hand, called the tarsus, Metatarsus, or five toes with nails, and three joints or articulations, but varying in number and forms into talons. These forms of termination distinguish between carnivorous and herbaceous, the former having prehensile organs, and the latter having no prehension with hoofs. The head is united to the atlas, or first vertebral joint, and the brain has two hemispheres, united by medullary laminæ, called corpus callosum, which has two ventricles and four pair of tubercles, the corpora striata, optic thalami, nates and testes. The optic thalami has a third ventricle, connected with a fourth below the cerebellum, which last is connected with the medulla oblongata by the pons varolii. In all mammalia the eye and ear are similar. The latter has its cavitas and membrana tympani, its pharynx, and its eustachian tube. The cavitas has four small bones called the incus or anvil, the hammer, and the stirrup. 1