THE OLFACTORY APPARATUS. 



179 



among the cells. The structure of the bulb in the sturgeon, 

 which is shown in Fig. 95, may be taken as typical for fishes and 

 amphibia. There are a great number of stellate and spindle- 

 shaped cells which enter into functional relations with the olfac- 

 tory fibers as in cyclostomes. The mitral cells also are well 

 developed and show essentially the same character as in higher 



N. olfactorius 



Fig. 95. — A horizontal section through the olfactory bulb of the sturgeon. 



vertebrates. They are very large cells lying in the fiber zone 

 which have thick dendrites with a comparatively small number 

 of branches. Each of these branches enters a glomerulus where 

 it divides into a very complex bush of end twigs. There also end 

 in the glomerulus the branches of a number of olfactory fibers. 

 These may subdivide repeatedly and bend back and forth, so 



