S02 CARTILAGINEI. SQUAXID^. 



The teeth of the Sharks constitute a most 

 formidable apparatus. They are generally tri- 

 angular, 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 exceed- 

 ingly 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 



