1820.] Royctt Academy of Sciences. 461 



position of this bone, whose thyroidean processes, which in the 

 mammaUa are directed backwards, and united with the thyroid 

 cartilage, ai-e here carried forward, and changed into a hngual 

 bone ; and lastly, from a removal of the sterninn, from the place 

 it occupied in the first three classes behind the clavicles, or the 

 OS coracoides, to the front of these bones where it is placed 

 under the throat. The lateral pieces which unite the arches of 

 the gills to the ligament which carries them, correspond, accord- 

 ing to M. GeoftVoy, with the points of ossification of the thyroid 

 cartilage, and with the arythenoid cartilages ; the lower pharyn- 

 gean bones with those of the cricoid cartilage ; the upper ones 

 to a flat piece which may have detached itself from the sphenoid 

 bone, or with the cartilaginous part of the eustachian tube ; the 

 branchial arches with those of the bronchiaj, and the small bones 

 which stand out from them to the rings of the trachea. We have 

 already given an account of these resemblances in our preceding 

 analysis, and we can now do no more than refer to the full 

 explanation which M. GeofFroy gives of them ; all the reasons 

 which induced him to give to each the degree of probability it is 

 susceptible of are there detailed. 



With respect to the third order of M. Geoffrey's ideas, those 

 concerning the really essential functions of the organs, it may be 

 asserted that they arise partly from the above-mentioned 

 researches, and have partly been formed in order to add weight 

 to the results he draws from these researches. 



. Consequently M. GeofFroy, being firmly convinced that the 

 perfectly developed bones which compose ihe gill covers offish, 

 and which in that class do not appear to serve for hearing, are 

 nothing else than the malleus, the incus, and the other small 

 bones of the ear of the mammalia on a larger scale, must have 

 been led to doubt whether these bones !\re the organs of hearing, 

 even in the animals in which they have always been considered 

 as such, and to regard them merely as a sort of superfluity 

 %vhich has remained incipient (these are his own terms) in the 

 animals with lungs, and indicative of an organization which is 

 vigorously necessary and amply developed in fishes. 



In the same way, having supposed that he found in the bony 

 apparatus of the gills, which produce no sound, all the bones of 

 the larynx, he has been induced to believe that " it is not upon 

 true and solid foundations that the larynx has been represented 

 as destined for the voice, as the principal organ of the voice," 

 and he prefers calling it " the first ring of the windpipe, the 

 station for the governors of the breathing organ, and the assem- 

 blage of its most zealous attendants." 



Nevertheless it is our duty to observe, that on the latter sub- 

 ject M. GeofFroy is not so hostile to the received opinion as the 

 efforts he makes to support his own might induce one to believe; 

 for he does not dispute that in animals with lungs the larynx 

 serves for the voice, and he even establishes a new theory to 

 explain how that organ performs this function. This is also the 



