The Motor Ganglion Cells of the Frog's Spiyial Cord. 81 



Explanation of Plates. 



Plates I and II are a graphic representation of the tables 

 X-XV., and. show the number of cells for each one-tenth mm. 

 of length of spinal cord. The vertical line marked O serves 

 as the axis of abscissas and contains as many units of 

 length as does the given cord one-tenth mm. On each side 

 are ordinates erected whose length corresponds to the num- 

 ber of cells at the given horizon. Each space on this axis 

 stands for ten ganglion cells. The figures are placed verti- 

 cally so as better to show the right and left, anterior and 

 posterior directions of the cord. In Fig. IV. the points of 

 exit of the nerves are marked. 



One source of error in the plates should be noted. It is 

 assumed that the sections were cut at right angles to the 

 spinal cord. Since this is never exactly true it happens that 

 a small bilateral asymmetry exists in the figure which may 

 not be found in the cord. 



Fig. I. see Table X., page 67. 



Fig. II. see Table XI., page 6S. 



Fig. III. see Table XII., page 69. 



Fig. IV. see Table XIII., page 70. 



Fig. V. see Table XIV., page 72. 



