ILLUSTRATION. 



Plate I. 



Fig. 1. Illustrating the course of the ductus nasofrontalis accessorius. The frontal 

 sinus, nasal cavity and neighboring structures of the right side are seen 

 from in front. The anterior part of the nose, the os nasale, most of 

 the os frontale and the anterior part of the maxilla have been removed. 

 The size and relations of the sinus frontalis and the first frontal cell are 

 well shown. The ductus nasofrontalis accessorius is seen to spring 

 from the inferior surface of the sinus frontalis, to run downward into 

 close proximity with the saccus lacrimalis in a dilatation, then to 

 proceed medianward (on the sutura frontolacrimalis) and on downward 

 (beneath the os nasale) terminating at its ostium in the anterior part 

 of the fossa nasalis. 

 2. The cellular ethmoidales, ductus nasofrontalis accessorius and lateral wall 

 of the nose of the right side seen from above and from the mesial side. 

 The relations of the first, second (sinus frontalis), third and fourth 

 frontal cells are to be seen. The upper portion of the third frontal cell 

 has been cut off to show its opening into the common vestibule. The 

 rudimentary ductus nasofrontalis can not be seen. The sinus frontalis 

 is slightly distorted to show the structures beneath its rnesian portion. 



479 



