l8o NERVOUS SYSTEM OF VERTEBRATES. 



that the glomerulus becomes an exceedingly complex interlacing 

 of dendrites and olfactory fibers. The glomeruli also receive 

 the dendrites of stellate and spindle cells (Figs. 96, 97) and some 

 small glomeruli are formed by the dendrites of these cells alone. 

 The transition from this to the condition found in mammals 

 could probably be found in reptiles but has not yet been studied. 



Fig. 96. — A spindle cell and two granules from the olfactor}- bulb of the sturgeon. 

 g, granules; gl., glomeruli; sp., spindle cell. 



In mammals the mitral cells are very highly developed and there 

 are in addition to them numerous cells with short neurites. (Fig. 98) 

 In the deeper parts of the bulb are a great number of small cells 

 which seem to have no neurites, and whose dendrites rise toward 

 the glomerular zone without entering the glomeruli. These are 



