682 Jacob Parsons Schaeffer. 



delayed. The question naturally arises : How far does the reduc- 

 tion in ethmoidal conchae progress? and what is the average 

 number of conchae in the adult in a large series of specimens? 



Naturally in the cases where the meatus suprema I is very 

 shallow and short, it becomes a personal equation as to whether 

 the shallow furrow should be considered as a meatus or merely 

 as a groove on the medial surface of the concha superior. In one 

 case it means an extra concha; in the other the whole ethmoidal 

 mass, superior to the concha media is considered as the concha 

 superior. This is doubtless the reason why writers differ so 

 widely in their results. Again, the accessory concha in the meatus 

 superior, when well developed, is at times erroneously considered 

 as the concha superior. This, of course, leads to divergent results 

 as to the number of ethmoidal conchae that are present in the 

 adult nose. 



Zuekerkandl in ''120 Kopfhalften" of adults found two eth- 

 moidal conchae in 24 of them, and three ethmoidal conchae in 

 96 of them. In this number he found his "mittlere Siebbeinmuschel 

 operkulisiert " in 11 instances. According to some of his figures 

 he has at times considered my accessory concha of the meatus 

 superior as his 'mittlere Siebbeinmuschel.' If we subtract 11 

 cases from the 96 and add them to the 24, we would presumably 

 have a better ratio for comparison with other results. The acces- 

 sory concha of the meatus superior is very prominent in some 

 adult noses, and a large number of specimens show at least a 

 Tudiinentary accessory concha. 



The fourth annual report of the committee of collective inves- 

 tigation of the Anatomical Society of Great Britain and Ireland, 

 gives the following results: Out of 152 observations, 3 cases are 

 reported with but one ethmoidal concha; 85 cases with two eth- 

 moidal conchae; 62 cases with three ethmoidal conchae; and 2 

 cases with four ethmoidal conchae. This report is the result of 

 fifteen subreports from as many different schools, with presum- 

 ably a larger number of observers. It is, therefore, difficult in 

 such a report to have uniformity in observation because, as 

 stated before, the personal equation as to what should be con- 

 sidered a concha in the cases where the differentiation is slight. 



