LARYNX OF MAMMALIA. 



5S5 



458 



the Kangaroos and Phalangers. The Opossums have the lower 

 ligament,, above which is a small f ventricle ': they can squeak 

 and also ' purr.' As a rule the Marsupials have little or no voice : 

 the Wombat emits a guttural hissing sound : the Dasyitrus Ur- 

 sinus a snarling growl or whine : the Thylacine is described as 

 uttering a short guttural cry. I have never heard a vocal note of 



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any kind from the Kangaroos, Potoroos, Petaurists, Phalangers, 

 or Perameles. Bennett l states that the Kangaroo utters a moan 



o 



when wounded and in pain. 



The voice of Rodents is shrill 

 and monotonous : the cry of the 

 wounded Hare is loud and pite- 

 ous. The alas of the thyroid, fig. 

 458, Z>, are quadrate, convex, and 

 united at an obtuse angle ; the 

 posterior margins are oblique 

 and parallel. The cricoid, ib. d, is 

 short or narrow anteriorly, leav- 

 ing a wide space for the crico- 

 thyroid ligament, ib. c. The 

 arytenoids, ib. ?i, n, are rela- 

 tively large, with everted api- 

 ces. The epiglottis, ib. , is 

 broad, with a bifid apex : at 

 its base are small cartilaginous styliform bodies, separated by a 

 triangular space : a vertical groove divides the insertions of the 

 ( chordae vocales ' from b to c. fio\ 458. The inferior tubercles, 



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<?, c, give attachment to the upper vocal cords ; which they help 

 to stretch, while they expand the ventricles, and afford freer mo- 

 tion to the lower vocal cords, d, d. In the Beaver the epiglottis 

 is triangular, with a vertical raphe on its posterior surface, termi- 

 nating in a sac bordered by the vocal ligaments. There is a blind 

 sac at the base of the epiglottis in Ccelogenys Paca : in both Ro- 

 dents the vocal cords are short and little salient, and the f ventri- 

 cles ' are shallow : the voice is acute. In the Porcupines both 

 the vocal cords and ventricles are wanting : they are mute, save 

 at the rut, when the male emits a low grunt. 



The Insectiuora agree with other Lyencephala in the low de- 

 velopment of the vocal organ and power. In the Hedgehog, 

 fig. 459, besides the thyroid, cricoid, c, arytenoid, d, and epiglottal 

 , cartilages, there is a triangular cartilage, f between the bases 



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of the arytenoids and the cricoid, called ' interarticular ' in 



1 CXCIl". 



Larynx of the Rabbit, 

 laid open from be- 

 hind, uat. size, cvrxx. 



Larynx and upper 

 part of trachea, 

 Rabbit, nat.size. 



