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H. W. NORRIS AND SALLY P. HUGHES 



Locy has stated that the olfactory cup in selachians is imper- 

 fectly divided by the development of a membranous fold from 

 the ring surrounding the entrance to the cavity, there resulting 

 two parts in the chamber, a mesial and a lateral. These two 



Fig. 2 A similar section slightly anterior to the preceding, and immediately 

 anterior to the olfactory bulb, through the two masses of olfactory fila. Section 

 412. X15. 



divisions in the olfactory cup are the result, as Berliner ('02) has 

 shown, of the early differentiation in the embryo of two groups 

 of Schneiderian folds or lamellae. These, however, have no 

 exact relation to the double nature of the olfactory nerve. Sund 



