COMPARATIVE ANATOMY OF THE LARYNX. 629 



tudinal elevation, formed by the anterior extremity of the 

 arytenoid*. 



Class II is a very large one, and embraces mammals from 

 very widely differing orders. 



The Hedgehogt belongs also to this class. 



In the Elephantl the arytenoids do not touch by their inner 

 surfaces, and the true cords are placed obliquely. The false 

 cords are indicated in position by a faint projection of the 

 mucous membrane, and the ventricles are only formed by an 

 excavation of the upper surfaces of the true cords. At the 

 anterior commissure there is a transverse fold. 



In the Euminants§ the arytenoids have, besides their articular 

 facette, a superior angle which is curved forwards, and an in- 

 ferior to which the vocal cords are attached. 



The inferior margin of these cords is obtuse and continuous 

 with the rest of the internal lining membrane, the superior 

 margin is more or less free and trenchant — it is much more so 

 in the Deer than in tlie Gazelles, and it is very indistinct in 

 the case of the Cow and Sheep. The internal fauces of the 

 arytenoids touch, and air could only pass between the anterior 

 margins and the epiglottis. This passage is more or less narrow 

 according to the species. There is no superior ligament and 

 no ventricle properly so called, neither does any cuneiform 

 cartilage exist. 



Sometimes, as in the Antilope guthtrosa,\\ the thyroid is 

 bulged outwards in the neighbourhood of the attachments of 

 the vocal cords. 



In Hares and Eabbits (Lepus timidus et cunicidus) there is an 

 intermediary form, as the false cords are wanting, but the 

 ventricle exists. In the Lepus timidus, however, Wolff denies 

 the existence of a ventricle. IF 



In the Eein-Deer** there is a large subepiglottal sac,but this 

 is not found in the Deer. 



The Sloth {Bradypus tridactylus) has a peculiar form of vocal 



* Cuvier, p. 791. f Milne-Edwards, p. 442. 



X Op. cit., p. 442. § Cuvier, p. 795. 



II Cuvier, p. 795. ^ WolfP, Dissertatio Anatomica, p. 19. 



** Milne-Edwards, p. 442. 



