ALTHOUGH NATURALISTS HAVE DIVIDED FISHES into two great tribes, the osseous and the cartilaginous, yet the distinction is not very precise; for the first have a great deal of cartilage, and the second, at any rate, a portion of calcareous matter in their bones.

The chest cartilage, except in an old deer, is soft; the ribs are thin and easily crushed, and the spaces between the ribs are wide enough to admit a man's finger, to say nothing of a wolf's fang.

Even such dense structures as bone, cartilage, and the teeth are formed from cells.

] Some cells live a brief life of 12 to 24 hours, as is probably the case with many of the cells lining the alimentary canal; others may live for years, as do the cells of cartilage and bone.

The cells are called connective-tissue corpuscles, cartilage cells, and bone corpuscles, according to the tissues in which they occur.

2. White Fibro-cartilage.

3. Yellow Fibro-cartilage.

[Illustration: Fig. 8.Fibro-Cartilage Fibers.

(Showing network surrounded cartilage cells.)] 25. Cartilage.

Under the microscope cartilage is seen to consist of a matrix, or base, in which nucleated cells abound, either singly or in groups.

It has sometimes a fine ground-glass appearance, when the cartilage is spoken of as hyaline.

This is called white fibro-cartilage, and is found where great strength and a certain amount of rigidity are required.

Again, there is between the cells a meshwork of yellow elastic fibers, and this is called yellow fibro-cartilage (Fig.

The hyaline cartilage forms the early state of most of the bones, and is also a permanent coating for the articular ends of long bones.

The yellow fibro-cartilage forms the expanded part of the ear, the epiglottis, and other parts of the larynx.

It adheres very closely to the bone, and covers every part except at the joints and where it is protected with cartilage.

Between the vertebræ are pads or cushions of cartilage.

A thin layer of soft putty may be put between the coins to represent the pads of cartilage between the vertebræ.

The principal structures which unite in the formation of a joint are: bone, cartilage, synovial membrane, and ligaments.

The joint-end of bones is coated with a thin layer of tough, elastic cartilage.

stone, pebble, flint, marble, rock, fossil, crag, crystal, quartz, granite, adamant; bone, cartilage; hardware; heart of oak, block, board, deal board; iron, steel; cast iron, decarbonized iron, wrought iron; nail; brick, concrete; cement.

Tenacity N. {ant. 328} tenacity, toughness, strength; (cohesion) 46; grip, grasp, stickiness, (cohesion) 46; sequacity^; stubbornness &c (obstinacy);; glue, cement, glutinousness^, sequaciousness^, viscidity, (semiliquidity) 352. leather; white leather, whitleather^; gristle, cartilage.

The cows and buffaloes are guided by a piece of thong, through the cartilage of the nose.

Tracing it upwards, I found it to be constituted by a prolongation of the ensiform cartilage of the sternum, or extremity of the breast-bone.

This joint has a motion upwards and downwards, and also a lateral motionthe latter operating in such a way, that when the boys turn in either direction, the edges of the cartilage are found to open and shut.