56 HUBER. [Vol. XVI. 



The pericellular plexuses of the simpler type resemble very 

 closely those to be described for birds and mammals. They 

 are found in all sympathetic ganglia, but are relatively more 

 numerous in the smaller ganglia. When the shape of the 

 enclosed cell can be ascertained, it will, as a rule, be found to 

 be multipolar. But as the sympathetic cells are generally only 

 imperfectly stained, when the pericellular plexuses are well 

 stained, the enclosed cells are usually not clearly made out. 

 The above statement may, therefore, be open to exceptions. 

 In PI. IV, Fig. 13, three of the simpler pericellular plexuses 

 are sketched. In each case the non-medullated axis-cylinder 

 (a collateral branch or end branch of a medullated fiber, as 

 one may occasionally trace such a branch to a medullated fiber) 

 breaks up, just before or after it pierces the capsule (not shown 

 in the figures), into several secondary branches, which, after 

 further division, are woven into a network varying greatly in 

 complexity and arrangement. The fibrillae of the network are 

 often very varicose, showing quite large nodular enlargements. 

 This network or plexus is generally seen as a closed one ; only 

 here and there some of the fibrillae seem to end free. (See b 

 of Fig. 13.) These plexuses are always intra-capsular, and sur- 

 round the cell body of a sympathetic cell ; the capsule, though 

 often not stained, may be recognized if much of the light is 

 cut off. 



The more complex pericellular plexuses vary greatly in struc- 

 ture ; they are usually found, as above stated, surrounding the 

 large unipolar cells. Their structure may best be made clear 

 by reference to a number of figures showing some of the dif- 

 ferent types found. In PI. IV, Fig. 16, the relation of such 

 an end plexus to the enclosed ganglion cell and capsule is 

 well shown. The axis-cylinder of the nerve fiber {a) ending 

 in the plexus breaks up into several branches, which are wound 

 around the single process of the sympathetic cell enclosed in 

 its end plexus. From these spirally arranged branches second- 

 ary branches are given off, which, on approaching the cell body 

 of the sympathetic cell, are woven into a loose basket-like net- 

 work. Very often the axis-cylinder ending in such pericellular 

 plexuses is spirally wound around the process of the sympa- 



