A description of the teeth of the Anarrhichas lupus Linnaei, and of those of the Chaetodon nigricans of the same author : to which is added, an attempt to prove that the teeth of cartilaginous fishes are perpetually renewed / by William Andre ; communicated by Sir Joseph Banks.

  • André, William, 1743-1807.
Date:
1784
Catalogue details

Licence: Public Domain Mark

Credit: A description of the teeth of the Anarrhichas lupus Linnaei, and of those of the Chaetodon nigricans of the same author : to which is added, an attempt to prove that the teeth of cartilaginous fishes are perpetually renewed / by William Andre ; communicated by Sir Joseph Banks. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    'wanting’then4 angles to the right, and the teeth on 'the right- .fide being deftitute of their angles to the left. As it is certain, that the anterior teeth were formerly pofle- -rior ones, and as the teeth in each row were all deficient in one .angle, it follows, that they muft have been formed pofterior to the infertion of this extraneous body. Again, if we allow that before the accident the animal was in pofieffion of perfedt teeth, it follows alfo, that ’ theywere confumed -and replaced by imperfect ones. There were fix teeth in each row, and fifty-two rows, -making togetiier about 312 teeth. Now allowing the con- -fumption to-have been equal in all parts of1 the jaws, it fol- lows, that the animal had already confumed 312 teeth, and .was in poffeffion of a like number for future confumption. The teeth of fharks, rays, &c. may be divided into adtive and paffive. The a6tive teeth are the anterior ones of each row, handing with their points upwards. The paffive teeth •are the remaining ones, lying one upon another, like the tiles upon a houfe (imbricated), with their points downwards. It appears from the foregoing account, that the anterior or adive teeth- had been replaced fix times; and that they might have -been renewed fix times more, making in all twelve times. From which, 1 think, we may reafonably conclude, that this does not happen any precife number of times^; but that the renovation is perpetual during the life of the animal. The longevity of fiffies is a fa£t pretty well eftablifhed. In addition to this part of natural knowledge, I have endeavoured to prove, that a part of the inhabitants of the great deep re- tain, in the article of teeth, a perpetual juvenility, being appa- rently utter Grangers to edentulous old age. i * 1 4 , I EXPLA-