Plate XX 



Fig. 22. Transverse frontal section of a human embryo of 22 millimeters, Colum- 

 bia Collection, No. 3, near the frenulum linguae, X 157. reduced j- 

 Slide 3, row 2, section 15. 



Fig. 23. The same embryo, slide 3, row 2, section 12, X 157. reduced 5. Sec- 

 tion passes through the junction of the greater sublingual anlage and 

 the subma.xillary duct. 



Fig. 24. The same embryo, slide 3, row i, section 10, X 157. reduced h. Section 

 passes through the dorsal accessory subma.xillary. 



/. Buccal sulcus. 



8. Lingual sulcus. " 



9. Subma.xillary duct. 



/(). Greater sublingual anlage. 



//. .\niage of apical gland. 



i^. .\lveolar sulcus. 



16. Intermediate sulcus. 



ig. Plica fimbriata. 



2 J. ^\lveolingual region. 



25. Palate process. 



,p. Lingual nerve. 



jf. Submaxillary ganglion. 



,^4- Ectopalatine sulcus. 



