646 Jacob Parsons Schaeffer. 



all cases. Of course after birth the meatus suprema I in many 

 cases becomes obliterated (62.5 per cent of my adult specimens 

 present a meatus suprema I) and in the adult the concha nasalis 

 superior and suprema I are represented by the concha superior. 

 The meatus medius and superior are, of course, constant in both 

 the fetus and in the adult. 



In a general way we may say that the integrity of the ethmoidal 

 meatuses present, with the possible exceptions of the meatus me- 

 dius and superior, depends practically wholly upon the differentia- 

 tion and degree of development of the descending rami, and not 

 upon the ascending rami (figs. 21 to 24). 



The nasal conchoe 



The concha nasalis inferior. The concha nasalis inferior appears 

 first in the formation of nasal conchae, and for some time occupies 

 the greater portion of the lateral nasal wall (fig. 13). It is at first 

 not well differentiated, but with the growth of the fold and the 

 deepening of the furrows (meatuses) inferior and superior to it, 

 the concha becomes more sharply outlined. With the growth of 

 the nasal fossa in the dorsal and superior direction, and the result- 

 ing development of the ethmoidal region, the concha inferior 

 gradually comes to take on the usual adult form. During the 

 latter stages of intrauterine life it offers nothing of note to justify 

 a further consideration of it in this connection. 



The agger nasi. The agger nasi is homologous with the nasotur- 

 binal which is so well developed in some other forms (pig, cow, 

 sheep, dog, skunk, etc.). It is extremely rudimentary in man in 

 comparison, for example, to the corresponding structure in the pig, 

 rabbit, cow, etc. The agger nasi is an elevation located ventral to 

 the concha nasahs media, and ventral and superior to the concha 

 nasalis inferior. It is more or less parallel to the bridge of the 

 nose. It is at times fairly well developed in the late fetus, and 

 again we find it extremely rudimentary (figs. 22, 25, 29, and 39). 



Kilhan, in conjunction with the processus uncinatus of the 

 ethmoid bone, considers it as an ethmoidal concha, i.e., belonging 

 to the ethmoidal group of conchae. He considers the processus 



