VOL. LXXVII.] PHILOSOPHICAL TRANSACTIONS. . 333^ 



Of the larynx. — The larynx in most animals living on land is a compound 

 organ, adapted for respiration, deglutition, and sound, which last is produced' 

 in the actions of respiration; but in this tribe the larynx I suppose is only 

 adapted to respiration, as we do not know that they have any mode of producing 

 sound. It is composed of os hyoides, thyroid, cricoid, and 2 arytenoid carti- 

 lages, with the epiglottis. It varies very much in structure and size, when com- 

 pared in animals of different genera. These cartilages were much smaller in 

 the bottle-nose of 24 feet long, than in the piked whale of 1 7 feet, while the 

 OS hyoides was much larger. 



In the bottle-nose, the os hyoides is composed of 3 bones, besides 2 whose 

 ends are attached to it, being placed above the os hyoides, making 5 in all. In 

 the porpoise, piked whale, &c. it is but one bone, slightly bent, having a broad 

 thin process passing up, which is a little forked; it has no attachment to the 

 head by means of other bones, as in many quadrupeds. The thyroid cartilage 

 in the piked whale is broad from side to side, but not from the upper to the 

 lower part: it has 2 lateral processes, which are long, and pass down the outside 

 of the cricoid, near to its lower end, and are joined to it much as in the human 

 subject. These differ in shape in different animals of this tribe. The cricoid 

 cartilage is broad and flat, making the posterior and lateral part of the larynx, 

 and is much deeper behind, and laterally, than before. It is extremely thick 

 and strong, flattened on the posterior surface, and hollowed from the upper 

 edge to the lower, it terminates by a thick edge on the posterior part above, 

 but irregularly at the lower edge, in the cartilages of the larynx. 



The 2 arytenoid cartilages are extremely projecting, and united to each other 

 till near their ends ; are articulated on the upper edge of the cricoid, but send 

 down a process, which passes on the inside of the cricoid, being attached to a 

 bag in the piked whale, which is formed below the thyroid and before the cricoid 

 cartilages; they cross the cavity of the larynx obliquely, making the passage, at 

 the upper part, a groove between them: the cavity at this place swells out 

 laterally, but is very narrow between the anterior and posterior surfaces. The 

 passage above, between the arytenoid and thyroid cartilages, is wide from side to 

 side, and is continued down on the outside of the processes of the arytenoid 

 cartilage, as well as between them, ending below the thyroid, which is follicu- 

 lated on its inner surface on the fore part of the cricoid cartilage. 



The epiglottis makes a 3d part of the passage, and completes the glottis by 

 forming it into a canal, in several of this tribe; but in the piked whale it was 

 not attached to the arytenoid cartilages, but only in contact, or inclosing them 

 at their base, so as to make them form a complete canal. I could not observe 

 any thing like a thyroid gland. From the glottis and epiglottis being so con- 

 nected as to make but one canal, and from the thyroid and cricoid cartilages 



