6C0 



.ANATOMY OF VEUTKBKATES. 



In the green Monkey ( Cercopithecus sabceus), the structure of 

 the larynx accords with that in Macacus ' and Cynocephalus. In 

 fig. 473, B shows the expanded and excavated basihyal, f, with 

 the attached thyiohyals : in A, a is the epiglottis, b the basihyal, 

 c the hyoid sac, d the thyroid cartilage, e the trachea. 



No tailless Ape has the medial aperture and hyoid sac. In 

 the Gibbons the larynx is relatively large, the vocal cords well 

 defined, with deep intervening ventricles, from one of which is 

 continued the sac projecting into the thyro-hyoid space. If 

 Mycetes has the loudest cry, the Gibbons have the greatest range 

 of nctes ; they alone, of brute Mammals, may be said to sing. I 



473 



474 



Larynx of Cercopithecus safoseus. cccxx. 



Laryngeal pouch of the adult Orang-utan. 



heard, with astonishment, the Wouwcu (Hylobates agilis), captive 

 at the Zoological Gardens, emit the rising and falling scale of 

 semitones, throughout the octave, which Martin has accurately 

 rendered in the musical notation given in ccxx". In the Orangs 

 the sacculi continued from the intercordal ventricles pass out be- 

 tween the thyroid and hyoid, and in the adult males extend 

 over the fore part of the neck and upper part of the chest, 

 being subdivided into several pouches, as in fig. 474, the lowest 

 of which may be crossed by the pectoralis major. In the young 

 Chimpanzee ( Troglodytes niger), the laryngeal sacculi, fig. 475, 

 a, a, produced from the ventricles extend upward and outward, 

 the left, in the specimen dissected by me, being continued for- 



xx. vol. ii. p. 110, fig. 1173 c. 



2 xx. vol. ii. No. 1173 a. 



