36 H. LISSER 



Fig. 1 Cross section of human Embryo no. 109 (10.5.) to show cricoid cartilage 

 and M. criooarytaenoideus posterior. V. C, vertebral cohimn; Esoph. L., Lumen 

 of esoi)hagus; constr., constrictor muscle; cri. post., M. criooarytaenoideus poste- 

 rior; n. r., nerve recurrens; cri. c, cricoid cartilage; thy. gl., thyreoid gland; B. C, 

 buccal cavity; L. L., larynx lumen. 



Fig. 2 Cross section of human Embryo no. 109 (10.5mm.) to show thyreoid cart- 

 ilage, M. criooarytaenoideus lateralis, M. thyreoarytaenoideus. Ph. L., Pharynx 

 lumen; >S. N. S., sympathetic nervous system; thy. c, thyreoid cartilage; n. XII, n. 

 hypoglossus; cri. lat., M. cricoarytaenoideus lateralis; thy. ary., M. thyreoarytae- 

 noideus. 



Fig. 3 Frontal section of human Embryo no. 317 (12.5 mm.) to show epiglottis 

 thyreoid cartilage, and hyoid bone. Ant. Card., anterior cardinal vein. 



Fig. 4 Frontal section of human Embryo no. 317 (12.5 mm.) to show superior 

 laryngeal nerve, sup. /ary., superior laryngeal nerve; car. a., carotid artery. (The 

 cricoarytaenoideus lateralis mass {eri. lat.) includes whatever there is of the 

 thyreoarytaenoideus muscle.) 



Fig. 5 Frontal section of human Embryo no. 317 (12.5 mm.) to show M. crico- 

 thyreoideus and arytaenoid masses. Ary. m., arytaenoid masses; cri. thy., M. 

 cricothyreoideus. 



Fig. 6 Frontal section of human Embryo no. 317 (12.5 mm.) to show M. cricoary 

 taenoideus posterior, interarytaenoideus and nerve recurrens. tr., trachea; int. 

 arij.. M. interarytaenoideus. 



