OCR Text |
Show FIRST GREAT DIVISION OF THE ANIMAL KINGDOM. ANIMALIA VERTEBRATA. The bodies and limbs of vertebrated animals being supported by a frame-work or skeleton composed of conn.ected pieces that are movable upon each other, their motions are certain and vigorous. The solidity of this support enables them to attain considerable size, and it is among them that the largest animals are found. The great concentration of the nervous system, and the volume of its central portions, give energy and stability to their sentiments, whence result superior intelligence and perfectibility. Their body always consists of a head, trunk and members. The head is formed by the cranium which contains the brain, and by the face which is composed of two jaws and of . the receptacles of the senses. The trunk is supported by the spine and the ribs. The spine is formed of vertebrre, the first of which supports the head, that move upon each other, and are perforated by an annular opening, forming together a canal, in which is lodged that medullary production from which arise the nerves, called the spinal marrow. The spine, most commonly, is continued into a tail, extending beyond the posterior members. The ribs are a kind of semicircular hoops which protect VoL. I.-E |