ספריה פדגוגית '00 AMPHIBIOUS ANIMALS. מס'. UNDER this title, as living occasionally both on land and in water, Linnæus has arranged the oviparous quadrupeds, usually denominated Reptiles, and the Serpents. It is true that it may be considered exceptionable on account of some individuals being c fined to only one of those elements: these are, however, so very few, as not, with any propriety, to affect the general denomination. Towards these animals mankind have ever entertained a great degree of abhorrence, originating in a dread of their supposed, and in some instances their undoubted poisonous properties, in the unpleasant sensation of touching cold animals, and in their often ugly and squalid forms. This abhorrence is so general, in all countries, and amongst all classes of people, that, even where the species are in themselves innoxious and beautiful, it is not without much difficulty to be overcome. To the philosopher, however, the various tribes afford an inexhaustible fund of instruction and delight: the form, destination, and importance of these animals in the grand scheme of nature, are truly admirable, and have been found amply to repay the care, the danger, and trouble of their investigation. By far the greater part of the species live in retired, watery, and shady places, where they seem stationed to prevent the excessive multiplication of water animals and insects; and themselves, in many instances, to serve as food for fishes and birds. They do not chew their food, but swallow it whole, the throat and stomach being capable of great distention, sometimes receiving animals of greater thickness than themselves in a natural state. Some, but not many of them, live on plants or flesh. They have a power of enduring abstinence that would infallibly prove fatal to most other orders of animals. Several of the species have been known to exist, and in apparent health and vivacity, for many months without food. They are able, from the peculiar structure of their organs, to suspend respiration at pleasure; and thus to support a change of element uninjured. It is generally asserted, and believed, that the hearts of the Amphibia are furnished with only one ventricle more accurate physiologists are, however, of opinion, that we ought rather so say that they have two ventricles, with an immediate communication between them. The blood is red, but cold, and in small quantity. The lungs consist, for the most part, of a pair of large bladders or membranaceous receptacles, parted into cancelli or small subdivisions, among which are beautifully distributed their few pulmonary blood-vessels. Many of the animals possess a high degree of reproductive power; and when their feet, tail, &c., are by any accident destroyed, others will grow in their place. Their bodies are sometimes defended by a hard horny shield or covering; and sometimes by a coriaceous integument. Some species have scales; and others soft pustular warts, or protuberances. Their bones are more cartilaginous than those either of quadrupeds or birds.-Several of the species are destitute of ribs.-Some are furnished with formidable teeth; whilst others are entirely without some again are fierce and predacious; and others perfectly inoffensive. In general, however, they are of a mild and peaceful disposition.-The bodies of the amphibious animals are cold to the touch. This circumstance, and their usually squalid and ugly form, have excited so great a disgust as partly to have founded the notion of all of them being venomous. Very few, however, except among the Serpent tribes, and even of these not more than onesixth of the species, possess this dreadful quality.They are all extremely tenacious of life, and some of them will continue to move and exert animal functions even destitute of their head or heart.-Their colours are often livid and disgusting; though some are decorated with most splendid skins. Many of them exhale a loathsome odour, owing perhaps to the foulness of their abode, or the substances on which they feed. Their voices are either harsh and unmusical, or else the animals are entirely dumb. Most of the Amphibia are oviparous. The Reptiles, therefore, or those that have four legs, are denominated oviparous quadrupeds, to distin guish them from the Mammalia, or viviparous quadrupeds. They are usually very prolific. The eggs of some species are covered with a hard calcareous shell; whilst those of others have a soft tough skin or covering, somewhat resembling parchment: the eggs of several are perfectly gelatinous. As soon as the parent-animals have deposited their eggs in a proper place, they take no further care of them, but leave them to be hatched by the sun. In those few species that are viviparous, the eggs are regularly formed, but hatched internally this is the case with the Viper and some others. In cold and temperate climates, nearly all the Amphibia pass the winter in a torpid state. During this season they are often found perfectly stiff, in holes under ice, or in water. They continue thus till revived by the returning warmth of spring. They then become reanimated, change their skin, and appear abroad in a new coat. Many of them cast their skins frequently in the year: those Reptiles, however, that have an osseous covering, as the Tortoises, never change it. The Amphibia, though they are sometimes found in great numbers together, cannot be said to congregate, since they do nothing in common, and in fact do not live in a state of society. The flesh and eggs of some of the species form a palatable and nutritious food. કે The Amphibia are divided by Linnæus into two orders; viz. Reptiles and Serpents. The Reptiles are furnished with legs. They have flat naked ears |