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H. W. NORRIS AND SALLY P. HUGHES 



lobe a posterior fibrous portion at whose periphery the olfactory 

 glomeruli gradually appear, in passing anteriorly section by sec- 

 tion. In the posterior part of the field of their appearance in 

 the sections an anatomical distinction between lateral and ventral 

 groupings of the glomeruli does not seem apparent, but proceed- 



Fig. 1 A cross-section of the right half of the head through the olfactory- 

 bulb and the extreme posterior border of the olfactory lamellae. Section 429 

 (fig. 51). X15. 



ing anteriorly there are soon seen three bands of glomeruli, 

 dorsal, lateral, and ventral. Anterior to the level where the 

 olfactory bulb appears separate from the brain in cross-sections, 

 the dorsal and ventral areas unite mesially into one, ventro- 

 mesial in position (fig. 1, glm.). 



