252 



THE HARMONIES OF NATURE. 



one half, and leaving the other for a second morsel ; and such is 

 the power of the seawolf s jaws, that he will crunch a cutlass as 

 if it was made of glass. 



The teeth of the fishes are not, like those of the quadrupeds, 

 consolidated with certain bones of the mouth, or implanted into 

 the jaws, but, like the scales, prickles, and spines, are of merely 

 cuticular origin. Hence they afford an amazing variety of form 

 and position, being attached to any or to every part of the 

 mouth, according to the necessities of the given species ; hence 



also their numbers are often 

 very large, and capable of 

 constant renovation. Some- 

 times they are so minute 

 as only to be perceptible by 

 the rough or scabrous sur- 

 face which the parts of 

 the mouth to which they 

 are attached present. If of 

 larger size, they exhibit 

 the appearance of a file or 

 rasp, or they may have the 

 shape of small cones or 

 hooks thickly scattered over 

 the mouth. 



In the sharks, they con- 

 sist of several rows of 

 broad arid trenchant lami- 

 nae, the anterior row of 

 which (a) stands up per- 

 pendicularly from the jaws, 

 ready for use, while the 

 succeeding layers (6) are re- 

 cumbent, being covered over by a fold of the mucous lining of 

 the mouth. These teeth, like those of the rays, are perpetually 

 renovated, new and sharp rows behind being constantly ready to 

 replace the old and worn ones in front, as soon as the latter fall 

 out or become useless. 



In the lamprey, which does not sever its victims by a powerful 

 bite, but sucks their blood like a leech, the teeth are very differ- 

 ently though not less admirably arranged; for here they are 



Teeth of Shark. 



c divided tooth to show that it is hollow, d fibro- 

 mucous layer, which by its growth brings the 

 successive rows progressively into use. 



