SKELETOIS" AND LARYNX OE 5EN0PUS AND PIPA. 77 



is of a very fragmentary and unreliable character, but he excuses 

 himself (42. p. 309) on the ground that his only material con- 

 sisted of a series of sketches drawn from a specimen dissected 

 several years before. His figures (42. Taf. 21. figs. 58 and 61) 

 are presumably reproductions of these sketches. 



Female. 



Dilator laryngis (PI. 10. fig. 2, J). — This dilator muscle of the 

 glottis, called by Henle (19. p. 27 and Taf. 2. fig. 5, m) the 

 " unterer Erweiterer," arises from the external and dorsal surfaces 

 of the posterior three-fourths of the thyrohyal, and partly also 

 from the roof of the larynx. ISTone of the fibres arise from the 

 floor; a point of some importance when considering sexual 

 differences. The anterior end of the muscle runs into an ex- 

 tensive aponeurosis, the fibres of which pass directly inwards, in 

 a direction transverse to the long axis of the larynx, and, after 

 passing over the ' blinker-shaped ' process of the laryngeal car- 

 tilage (PI. 8. fig. 3, &/.), are inserted into the dorso-external edge 

 of the massive posterior enlargements («r.') of the arytenoid 

 cartilage, and into the posterior part of the arytenoid (ar), 

 guarding the glottis. The anterior part of the insertion of this 

 muscle is not tendinous. No great diflSculty besets the determi- 

 nation of this muscle, for, since it runs from the hinder part of 

 the thyrohyal to the outer surface of the arytenoid, it evidently 

 corresponds with the dilator laryngis * of other Anura. 



The part of the muscle that arises from the roof of the larynx 

 (PI. 10. fig. 2, d') also spreads on to the thyrohyal, beneath the 

 greater belly of the dilator. It is separable from the latter, and 

 its tendon, which is abou:t as long as the muscle itself, passes 

 along the dorso-internal border of the thyrohyal, and, running 

 in a groove between the roof and side of the larynx proper as 

 around a pulley, is attached to the postero-externo-dorsal 

 corner of the arytenoid enlargement. The relations are not 

 such as to warrant the recognition of this as a distinct muscle. 

 That the dilator muscle should spread from the thyrohyal inwards 

 on to the roof of the larynx is not exceptional, for in the frog a 

 few of the fibres of this muscle arise from the cricoid cartilage 



* Dilatateur, Saint-Ange, 36- p. 421, and PI. 26. fig. 3', d'. 



Hyo-ex-glottique, Duges, 10- p. 126, and PI. vii. (bis), fig. 47, no. 26. 

 Oeffner des Stimmladeneingangs, Henle, 19- p. 23. 

 Dilatator laryngis, Ecker, 12- p- 315, and Goppert, 16. p. 63. 



