The teeth of the Sharks constitute a most formidable apparatus. They are generally triangular, very sharp-pointed, and often have a small point on each side the principal one; they are flat, and the edges are keenly cutting, so that they resemble lancets; moreover, in some cases, the edges themselves are notched into minute saw-like teeth. Each of these lancet-teeth alone, in a Shark of considerable size, would inflict a severe gash; what then must be the effect of a whole mouthful of such weapons, above and below, arranged in serried order, rank behind rank, and moved with the force of powerful muscles? The teeth of a fossil Shark are found two inches and a half in diameter, from base to point.
The mode by which the race of these formidable creatures is continued, differing as it does so greatly from that of most other fishes, is exceedingly curious. The Shark, instead of depositing some millions of eggs in a season, like the Cod or the Herring, produces two eggs, of a square or oblong form, the coat of which is composed of a tough horny substance; each corner is prolonged into a tendril, of which the two which are next the tail of the enclosed fish are stronger and more prehensile than the other pair. The use of these tendrils appears to be their entanglement among the stalks of sea-weeds, and the consequent mooring of the egg in a situation of protection and comparative security. Near the head there is a slit in the egg-skin, through which the water enters for respiration, and another at the opposite extremity by which it is discharged. That part of the skin which is near the head, is
