KAND: nervous system of LUMBRICIDiE. 113 



as forming the third class of coustituents of the fixed cell, may be more 

 prominent because of their greater size and their frequent occurrence 

 within a clear area. But these larger masses diflfer from the central 

 granule in being less deeply stained and less sliarply outlined. The 

 central granule is conspicuous as compared with any bodies in the finely 

 granular cell substance. "When once found, it is generally very easy to 

 distinguish it from other elements contained in the cell body. 



The position of the central granule is characteristic. It always lies in 

 the part of the cell opposite the nerve process, and very nearly in the 

 long axis of the cell. It is generally very near the nucleus, as in 

 Figures 2 and 3 ; but it may be farther away, as in Figure 4, especially 

 if much the greater bulk of the cytoplasm is on that side of the nucleus. 



The central body of Figure 1 is a single minute granule, and is spher- 

 ical, as nearly as could be determined for a thing so small. It lies at 

 the centre of a very small spherical space which appears in the section 

 as a narrow clear area about the granule. The clear area is not sharply 

 outlined. 



Several extremely delicate radiating fibres extend outward from the 

 central granule into the surrounding cytoplasm. Those represented in 

 the figure all lay in a plane parallel to the surface of the section. It 

 was rarely possible to detect a fibre if it was so oblique that it did 

 not come into the focal plane all at once. Generally not more than six 

 or eight of these fibres could be detected. In all of the first nine figures 

 can be seen fibres which extend well out toward the periphery of the 

 cell. Many of the radiations, however, could not be traced so far. So 

 fine are these radiations that it is only with the greatest difficulty that 

 anything as to their nature can be made out. The more conspicuous 

 radiations appeared to be made up of minute granules arranged in line. 

 The finer radiations show no evidence of granules, appearing rather as 

 most delicate hyaline threads. However, radiations were found exhibit- 

 ing both characters at different parts of their course. It is therefore 

 probable that these radiations consist of achromatic fibrils bearing 

 more or fewer granules along their courses. The granules may be so 

 thickly set that the radiation appears as a line of granules, or they 

 may be absent, when only the achromatic fibril can be seen. 



If a distinct radiation be carefully traced, it will be seen that at inter- 

 vals there occur some fairly conspicuous granules, which are more easily 

 seen because of a surrounding clear space. Figures 1, 2, and 3 show this 

 to some extent, but the fact is much more clearly brought out in some 

 of the regenerated cells to be described later (Plate 2, Figures 10-13). 



