138 



J. PARSONS SCHAEFFER 



difficulty in interpreting the anatomy of the nasofrontal connec- 

 tions in this specimen. Did the sinus frontalis develop from the 

 infundibulum ethmoidale (by a direct extension or from an in- 

 fundibular cell) or from the second frontal pit (early cellula 

 ethmoidalis anterior) ? 



The infundibulum by its ventral and cephalic extension usually 

 comes into topographic relationship with some of the cellulae 



Celbila etk.a/d. I frontal fo^o^m/jJt^j ^ 



Cfl.Mae etJL ant. frmd.). ^ ^ -.Cv.V— - jl^ 



Fig. 9 Dissection from an adult. Xote the two sinus frontales, the absence 

 of ductus nasofrontalis, and thc> ventral termination of the infundibulum eth- 

 moidale. See text. 



ethmoidales anterior which arise from the frontal pits. In this 

 instance (fig. 8), a relationship may early have been established 

 with the second frontal pit (there is e^'idence in support of this 

 belief). 



Resorption of the intervening barrier would, of course, bring the 

 infundibulum ethn:ioidale in direct continuity with the cellula eth- 

 moidalis anterior arising from the second frontal pit, likewise 

 with the sinus frontalis. The dissection gives positive evidence 

 of three frontal pits (now cellulae ethmoidales anterior). Whether 



