584 



ANATOMY OF VERTEBRATES. 



Larynx opened from behind, Ornitho- 

 rhynchus, magn. cccxx. 



thyroid process, y, f, fig. 456, the superior vocal cords are shown 

 at b, b, the inferior ones at c, c : they are short, feeble, with a 

 shallow linear interspace : a sulcus, <7, lies between the upper 

 cord and the cricoid cartilage. Both sexes emit a feeble squeak. 

 j- The epiglottis, in Marsupials, is 



remarkable for its laro;e size, and 



O 



generally for its emarginate apex. 

 There is no muscle passing from the 

 epiglottis to the tongue; its base is 

 connected in the Kangaroo by a tri- 



^j / 



angular fascia to the body of the os 

 hyoides and the greater cornua ; and 

 a small muscle passes from the middle 

 part of the body of the os hyoides to 

 the dorsum linguae. In Didelphis 

 Opossum the epiglottis, fig. 456, /, is 

 entire, the thyroid, ib. a, short, antero- 

 posteriorly produced, and bifurcating 

 into upper and lower cornua behind : 

 the cricoid, b, c, is broad behind and 

 notched below. In the Phalano;ers the 



o 



epiglottis is broad and short, and with a bifid apex. In Pera- 

 meles and Phascogale the sides of the broad and short epiglottis 

 are attached to the apices of the arytenoid cartilages, retaining 



thus much of its early condition, which 

 will be adverted to in the account of the 

 peculiarities of the mammary foetus. In 

 the Perameles lagotis I found on the base 

 of the tongue in front of the epiglottis a 

 small sacculus of mucous membrane, 

 which communicated by a regular sym- 

 metrical crescentic aperture situated 

 between the body of the os hyoides and 

 the thyroid cartilage, and was continued 



v C3 * 



down in front of the thyroid cartilage : 

 the surface of the cavity was smooth and lubricated, and it 

 seemed to be for the purpose of facilitating a hinge-like motion 

 between the thyroid cartilage and the body of the os hyoides. The 

 thyroid cartilage is com ex externally and protuberant in the 

 Phalangers and Koala. The base of the arytenoid cartilages is 

 broad in the antero-posterior direction. The chordae vocales are 

 represented by short and slight folds of the membrane, want- 

 ing the ' ligaments,' and not susceptible of being stretched, in 



457 



Larynx of the Opossum. 

 cccxx. 



