404 



Nose, Pharynx and its Derivatives in Man - 



still possible to trace the line between the two surfaces of the cells'. 

 Later even this is impossible. 



Seen from the side, as in Fig. 8, this model presents a covered out- 

 line, almost U-shaped. The 1st visceral pouch (Eustachian tube) pro- 

 jects outward .decidedly. It is elongated and thin rather than tubular. 

 On its under side there is a ridge near the end and a complication of 

 its outer end by a slight depression. What remains of the 4th visceral 



TP"- 



N: 



TP;- 



*FiG. 9. Lateral view of the model of the nose and pharynx of embr^'o XLIII. 

 Magnified 15 diameters. Hyp., hypophysis; N., nasal cavity; Sub. mx. gl., rudi- 

 ment of submaxillary gland; Thym., thymus; Thyr., thyroid gland; T. p.^, depres- 

 sion caused by the inferior turbinate process; T. p/^, depression of the middle turbi- 

 nate process ; V. P., first visceral pouch. 



pouch is completely cut off from the cavity of the pharynx, but the 

 large lateral thyroid rudiments are still easily recognized as such, 

 although both have now fused with the median rudiment. 



Seen from above there is still a slight elevation where the hypophysis 

 joined the mouth. The large ridge running between the nasal cavities 

 is not so prominent and the cavities themselves are relatively much 



