Sargent, Giant Ganglion Ceils of Ctenolabrus. 1 9 1 



From the examination of a single cell of this kind a quite dif- 

 ferent interpretation would be possible, namely that the lighter 

 area is the nucleus and the darker substance a differentiated 

 cytoplasm aggregated about the nucleus. The examination of 

 several hundred cells preserved and stained by a variety of 

 methods shows that this is not the case. 



The cytoplasm has the characteristic shining appearance 

 of a highly refractive substance. Under a 1-12 in. oil im- 

 mersion it shows a finely granular structure. The chromoph- 

 ilic granules are elongated and lie with their long axes parallel 

 and concentric with the cell wall (Fig. 5). They are most con- 

 spicuous in the dorsal and larger end of the cell, gradually fading 

 out toward the point from which the axis cylinder comes off. 

 The cytoplasm lies principally in the lower part of the cell, but 

 usually may be seen to extend around the periphery of the 

 cell. In cells having the form of those in Fig. 4 the nucleus is 

 approximately spherical and lies in the upper part of the cell, 

 the cytoplasm having the appearance of having been crowded 

 downward, 



Neurites. — As has already been stated, the cells are in general 

 unipolar giving off a large neurite which passes ventrally into 

 the cord (Fig. 3). The course of the neurite may be directly 

 ventrad, or obliquely inclined cephalad or caudad, or again it 

 may run horizontally near the surface for a distance of five or 

 six diameters of the cell before passing downward into the 

 cord. Rarely a neurite is seen to pass out laterally from the 

 cell and become lost in the grey substance. The neurites of 

 anterior bilaterally placed cells run caudad near the surface of 

 the cord for some distance, then curving ventrad, laterad, and 

 cephalad pass forward through the fiber bundle. The neurite 

 having passed down one-half or two-thirds the distance to the 

 canalis centralis curves gradually either to the right or left, 

 sometimes dividing and finally enters or sends one of the two 

 branches into the lateral bundle made up of similar fibers. The 

 neurites pass alternately to the right or left, but this does not 



