658 Jacob Parsons Schaeffer. 



lateral wall of the descending ramus of the meatus medius/ If 

 we take into consideration the extreme cases found in the late 

 fetus we have thus formed four folds and four furrows. These 

 folds may appropriately be named superior and inferior bullar 

 folds, infundibular fold, and processus uncinatus; the furrows, 

 the suprabullar furrow or recess, the bullar furrow, the infrabullar 

 furrow, and the infundibulum ethmoidals The suprabullar 

 recess and the infundibulum ethmoidale are constant and are the 

 most important furrows. The others are of less importance and 

 are more irregular and inconstant in their development (figs. 

 31 and 34). 



Killian, who has studied this region extensively, finds a sim- 

 ilar number of folds and furrows on the lateral wall of the middle 

 meatus. He, however, considers the processus uncinatus as the 

 descending crus of his 'erste Hauptmuschel,' hence includes it 

 in the class of regular ethmoidal conchae. My superior bullar, 

 inferior bullar, and infundibular folds or conchae correspond to 

 his 'obere, mittlere, und untere Nebenmuscheln,' respectively. 

 My suprabullar, bullar, and infrabullar furrows, and infundibu- 

 lum ethmoidale correspond to his 'Recessus superior, obere 

 Zwischenfurche, untere Zwischenfurche, und Recessus inferior,' 

 respectively. 



The suprabullar furrow or recess. The suprabullar furrow or 

 recess is practically constant. It varies somewhat in its form and 

 extent, but all specimens give some evidence of it. At times it 

 continues ventrally and superiorly almost to the cribriform plate 

 of the ethmoid bone (fig. 38) ; however, in the majority of cases 

 it does not extend so far, due to partial fusion between the supe- 

 rior border of the superior bullar fold and the attached border of 

 the concha media (fig. 41). It is frequently also limited inferiorly 

 and dorsally by similar fusion. Again, there may be multiple 

 points of fusion between the superior bullar fold and the concha 

 media, thus breaking the suprabullar recess or furrow into sev- 

 eral compartments (fig. 43). The recess in many cases early 

 tends to deepen or pouch laterally and inferiorly behind the bullar 

 folds (fig. 35). In this manner the bulla becomes more or less 

 shell-like in structure; and some of the so-called bullar cells are 



