654 Jacob Parsons Schaeffer. 



ing crus. The descending crura of the conchae supremae II and 

 III, are variable and frequently entirely wanting. At times the 

 latter two are fused into one, and then in turn closely associated 

 with the anterior surface of the body of the sphenoid bone, in 

 the region of the developing sinus sphenoidalis. The concha 

 suprema III loses its identity early by becoming associated with 

 the anterior surface of the body of the sphenoid bone. 



Lobules and nodules of the ethmoidal conchae. At the junction 

 of the ascending and descending crura, or in the region of the 

 knees, we frequently find overhanging lobule formations. This 

 is a fairly constant condition for the concha media, and it is 

 also very common for the concha superior (figs. 21 and 28). 

 Occasionally the concha suprema I also presents a similar for- 

 mation, which in some cases more or less overhangs the supreme 

 meatuses and conchae. In the latter case it really amounts to 

 the ascending crura of the supreme conchae (fig. 30). Schwalbe 

 in his ''Anatomie der Sinnesorgane," refers to the lobule of the 

 concha nasalis media as the 'Operculum meatus narium medii.' 

 He does not, however, refer to similar formations of some of the 

 other conchae. Frequently there is a secondary thickening on 

 the middle of the lobules. Zuckerkandl calls attention to this for 

 the lobule of the concha media; however the other lobules fre- 

 quently present the same condition (figs. 25 and 30). Kilhan 

 refers to this secondary prominence as the 'Nodulus lobuh.' 

 Fig. 30 shows three well formed lobules — the superior one more or 

 less operculating the conchae and the meatuses in the immediate 

 vicinity. The lobule of the concha media is at times very prom- 

 inent, and it takes on different shapes as is evidenced by figs. 



21 and 25. 



My studies have led me to agree with the statement of Peter, 

 namely, that "Dieser Lobulus mit Nodulus ist der vorderen 

 Spitze der Ethmoturbinaha der Saugetiere zu vergleichen." 



Grooves on the concha nasalis media. The concha nasalis media 

 needs further consideration separately, since it presents grooves 

 or furrows on its medial and inferior surfaces (figs. 22, 23, and 

 25). These furrows which show on the mucous membrane cov- 

 ering the concha, generally present corresponding depressions in 



