208 



ELEMENTS OF MAMMALIAN ANATOMY. 



Each nerve cell presents two kinds of processes, proto= 

 plasmic processes or dendrites and an axis=cylinder pro= 



cess (Fig. 97). The dendrites, except in the ganglia 

 outside of the central nervous system, are usually several 

 in number and comparatively short, while there is but 



FIG. 97. CELL FROM THE CENTRAL NERVOUS SYSTEM. 100. 



a, Dendrites or protoplasmic processes; ax, axis-cylinder process; n, 



nucleus of the cell body. 



one axis-cylinder process from each cell, which may 

 be more than a foot in length. A number of axis-cylin- 

 ders (nerve fibers), each of which is surrounded by a 

 sheath, the neurilemma, constitutes a nerve bundle 

 or nerve. Every axis-cylinder or nerve fiber originates 

 in a cell, but terminates freely either within the central 



