4G H. LISSER 



The aryiaenoids are still represented by a roughly oval mass of 

 condensed mesenchyma, with no accuracy of form or outline. 



The aryiaenoids are still represented by a roughly oval mass of 

 condensed mesenchyma, with no accuracy of form or outline. 

 Fig. 10 is a reconstruction of one of them from a lateral view. 

 The mass is continuous with the cricoid mass, as indicated by the 

 cross lined area, (fig. 14) but its main arytaenoid portion is stained 

 deeply enough to differentiate it absolutely from being a part of 

 the cricoid mass. 



The epiglottis shows but little advance over its condition in the 

 earlier embryos, except for some gain in length over breadth, but 

 the mass out of which it assumes its adult shape, is easily recog- 

 nized. 



The hyoid hone and styloid process begin to show small areas of 

 chondrification, and their appearance is seen in a reconstruction 

 fig. 13 and 14. The attachment of the middle constrictor to the 

 greater cornu is shown in fig. 11. 



THE MUSCLES 



In a 14 mm. embryo Strazza says that a muscle mass, of spindle 

 shaped formation can be made out laterally in cross sections, but 

 that no distinct muscles can be isolated at this stage, and that 

 the mass simply represents laryngeal musculature. And at 16 mm. 

 he distinguishes a muscle band, bending around with the posterior 

 convexity, which in its upper portions he calls the arytaenoideus 

 transversus (interarytaenoideus), but considers this band a con- 

 tinuous muscle mass, only differentiated later by the development 

 of the cartilages. Further down he thinks it to be the cricoary- 

 taenoideus lateralis and thyreoarytaenoideus, but says it is con- 

 tinuous with the above, only spread over a greater area. So he 

 calls the larynx musculature an arch, which however, is not en- 

 tirely horizontal, but goes from above and behind, to below and in 

 front. Now it is true that considerable interlacing of fibres exists 

 at this stage, but not much more than occurs in careful dissections 

 of the adult larynx. It is also true that further separation and 

 development of the cartilages will bring about clearer differentia- 



