52 KANSAS UNIVERSITY SCIENCE BULLETIN. 



look much like hoops. In most cases the long axis of the 

 nebenkern is at right angles to the axis of the spindle from 

 which it was formed, while the stride, or dark lines, are in 

 planes parallel to it, as is seen in figs. 7 and 8a. In a few 

 cases the lines are parallel to the long axis of the nebenkern, as 

 shown in fig. 86. Fig. 9 exhibits a partial end view of the 

 nebenkern, while fig. 26 represents a polar view in all planes. 



The fibers in figs. 4 and 5 are not all in the same plane, giv- 

 ing frequently, with changing focus, the impression that the 

 lines are the edges of plates. Even in figs. 7 and 8, the ap- 

 pearances shown made me hesitate for some time before I dared 

 say that the lines represent stride on the surface and not plates 

 extending through the body. But the end views (figs. 9 and 26) 

 and the two drawings in fig. 19 show clearly that we are deal- 

 ing with encircling hoops and not dividing plates. Just how 

 or why the fibers bend and assume the shape of figs. 7 and 8 I 

 am not able to say, but I am sure it is not an artefact, as might 

 be supposed, because I have found them occupying whole cysts 

 of several testes, and nearly all of them were as regular and 

 definite as fig. 7. 1 



I have found the nebenkern in its perfect condition (fig. 7) 

 only in material fixed in Flemming ; although Zenker's fixation 

 showed some of the breaking-up stages. This may be due 

 partly to poorer fixation in other mixtures and partly to chance, 

 as not so many testes fixed in other agents were examined, and 

 the appearance evidently represents a very brief stage. These 

 fibers now begin to break up, and we get figures that remind 

 one of Meves's "mitochondrion korper" ; that is, a darker stain- 

 ing center and radiating lines to the outer ring. (Fig. 11.) Some- 

 times stages a little later recall Paulmier's "blackberry stage." 

 ( Figs. 12 and 25. ) Fig. 19a is a surface view and fig. 196 an op- 

 tical section of a nebenkern that is in the process of breaking 

 up. Figs. 20 and 21 have a part of one end cut off, while fig. 

 23 is a polar view. Fig. 22 is probably a forming blackberry 

 stage. 



All the above are brief stages, and we soon get the appear- 

 ance of figs. 13-16. Here we have the darkly staining central 

 ball surrounded by a clear space, enclosed by a ring, as Meves 



1. Professor McClungr, Mr. Sutton, and Mr. Blackman, of Kansas University, and Doctor 

 Child and Mr. Harper, of Chicago University, have seen my preparations, and all confirm my 

 statement that the appearance is not an artefact. 



