CLASS VI. Mammalia. - Suckle their young; red corpuscles double concave; heart with four cavities; lungs; diaphragm; body hairy; two occipital condyles. SUBCLASS I. Prototheria; Cloacal Mammalia. Order 1. MONOTREMATA. - Duck-billed; webbed feet: Ornithorhynchus. PROVINCE III. Mammalia. Order 3. SIRENIA. Herbivorous cetaceans; nostrils at the end of the snout; molars in both jaws: Manatus. with tusks and proboscis: Elephas. teeth wanting: Balana. teeth in lower jaw: Physeter. teeth in both jaws: Deiphinus. Vegetarian; large, flat molars; pinnigrade: Phoca. Order 5. CARNIVORA. - Flesh eaters; claws; canines well developed; molars trenchant; Order 6. Order 7. Order 8. RODENTIA. Canines wanting: incisors highly developed: Mus. INSECTIVORA. - Molars with sharp points: Scalops. CHEIROPTERA. - Fore limbs webbed for flight: Vespertilio. Order 9. PRIMATES. Arboreal; small; clawed; kidney-shaped nostrils; eyes and ears large: Lemur. Four incisors in each jaw; great toe nostrils apart: Cebus. teeth uneven ; with flat nail; nostrils close: Simia. teeth even; erect: Homo. CHAPTER IV MINERALS AND ORGANIZED BODIES DISTINGUISHED Nature may be separated into two great kingdoms,that of mere dead matter, and that of matter under the influence of life.62 These differ in the following points: (1) Composition.—While most of the chemical elements are found in different living beings, by far the greater part of their substance is composed of three or four, — carbon, oxygen, and hydrogen; or these three with the addition of nitrogen. Next to these elements, sulphur and phosphorus are most widely distributed, though always found in very small quantities. The organic compounds belong to the carbon series, and contain three, four, or five elements. The former class, comprising starch, sugar, fat, etc., are relatively stable. The latter, possessing the three elements named, with nitrogen and sulphur or phosphorus, are very complex, containing a very large number of atoms to the molecule, and are usually unstable. Here belong albumen, myosin, chondrin, etc., the constituents of the living tissues. The formula for albumen is said to be C2H112N18SO22, or some multiple of this formula. These compounds also contain more or less water, and usually exist in a jellylike condition, neither solid nor fluid. All organic compounds are formed through the chemical activities of protoplasm, which is the only living substance. Inorganic matter may, under its influence, be changed to orgànic, and vice versa; dead matter which enters the body of organized beings in the form of nutriment is |