16 H. W. MARETT TIMS. 



the epiglottis abutting against the posterior free (mesial) border of the palate. At 

 this stage the aryteno-epiglottic folds are in close apposition, so that the cleft between 

 their margins lies in the horizontal plane, whereas the true rima glottidis is vertical 

 (fig. 15). The relation of the parts agrees in considerable detail with the description 

 given by Waldeyer of the larynx in the Manatee (12). The iutra-uarial position of the 

 epiglottis at an early foetal stage is interesting, in connection with the question as 

 to whether this condition is a secondary one in the Mammalia or not. The late 

 Professor Howes (5), after bringing forward a considerable amount of evidence, 

 concluded that a consideration of the facts " weighs heavily against the supposition 

 that the introduction of the epiglottis into the narial pharynx can have been a 

 secondary process," and further, " as the case stands the facts point to the uselessness 

 of the epiglottis in deglutition, and, to my thinking, to a primary association in 

 mammals between that organ and the velum palati for purposes of respiration 

 exclusively through the nostrils." 



In order to more effectually shut off the respiratory passage from the gullet the 

 posterior margin of the velum palati grows backwards on either side of the larynx to 

 become, in later foetal life, united with the dorsal wall of the oesophagus, the food 

 having therefore to pass either to the right or left of the larynx. 



Even in the oldest specimens at my disposal there is no trace of any tubular 

 prolongation of the larynx and epiglottis such as is present in the Cetacea ; indeed, 

 the epiglottis in these seals is relatively diminutive. The particular adaptation here 

 present to prevent the entrance of water into the lungs approaches much more closely 

 to that of the Sirenia than to that of the Cetacea. 



The high pitch of the voice referred to by Dr. Wilson is probably due to the 

 relative shortness of the vocal cords. 



The only other fact to record in regard to the larynx is that I was unable to 

 detect the existence of the cartilaginous nodule lying in the thyro-hyoid ligament 

 which Dr. Murie found to be present in the Sea-lion (Otaria jubata), or of the 

 somewhat similar nodule, described by Howes, lying along the inner edge of the 

 posterior corner of the hyoid bone which he regarded as a " remnant of one of the 

 post-oral visceral arches such as are now known ... to exist in the urodele amphibia." 



The trachea passes backwards with a considerable ventral curve. Owing to the 

 curvature of the cervical spine, to which reference has already been made, it lies to 

 one side of the median line (in the specimen examined the trachea was to the left 

 side). The trachea bifurcates into a right and left bronchus, the right being in almost 

 direct continuation with the trachea itself. The eparterial bronchus is given off from 

 the right side of the trachea on a level with its bifurcation. 



The right lung has the usual three lobes of the Mammalia, the left lung being 

 bi-lobed. Of the two the right lung is much the more massive. Owing to the great 

 dorso-ventral obliquity of the diaphragm, the postero-dorsal margins of both lungs 

 are prolonged backwards for some considerable distance ; but, a condition which one 



