Lateral Wall of the Cavum Nasi in Man. 615 



are: (1) the nasal meatuses and the nasal conchae; (2) the acces- 

 sory furrows and the accessory folds (conchae) ; (3) the anlages of 

 the sinus paranasales. 



The materials used in this investigation include the following: 



a. Human embryos at successive ages from 21 days up to the 

 fetus at term; 



b. Fifty lateral nasal walls of new-born children; 



c. Twenty lateral nasal walls of children, ranging in age from 

 birth to 15 years; 



d. One hundred and fifty adult lateral nasal walls, ranging 

 in age from 15 to 88 years; 



e. Embryological and adult specimens of the lateral nasal wall 

 of the cat, dog, muskrat, woodchuck, skunk, monkey, pig, 

 sheep, and cow. 



The lateral wall of the nasal cavity of human embryos, aged 

 respectively 35, 43, 49, 58, 70, 83, 103, 120, 210, and 280 days, 

 was modeled by the blotting-paper method. Some of the models 

 were sectioned at appropriate planes to facilitate a more detailed 

 study of parts. In a number of instances the nasal fossae were 

 also reconstructed, in order to aid in a better understanding of 

 certain developmental stages. Through the kindness of Mrs. 

 Gage, who had previously modeled a 21-day human embryo, I 

 had the privilege of studying this region at this early stage of 

 development. 



The ages of all the human embryos studied were determined by 

 the Mall-method (Catalogue of the collection of human embryos in 

 the anatomical laboratory of the Johns Hopkins University, 

 Baltimore, 1904). 



I wish to take this opportunity for expressing grateful acknowl- 

 edgment to Professors Kerr, Kingsbury, and Tinker for helpful 

 suggestions. I also wish to express my appreciation of the abun- 

 dant material and other facilities placed at my disposal by the 

 departments of Anatomy, and Embryology and Histology. To 

 Professor and Mrs. Gage, for many courtesies extended during 

 this piece of research, I wish to express thanks. 



