Cytological stAidies on the spinning glands of Platyphylax etc. 411 



its even structure, due to a tendency of the striae to enter it. Bet- 

 ween the outer margin of the nucleus and the tunica propria the cyto- 

 plasm shows a very uneven structure due to the presence of two 

 optically different parts. These are the same as we have already 

 mentioned; the darker instead of the lighter areas now predominate, 

 and are especially numerous near the surface of the gland. The 

 striated appearance is not so pronounced, the striae extending, as before, 

 from the outer region of the cell to the nucleus, around the surface 

 of which they bend. Along the inner margin of the nucleus is a very 

 deeply colored layer of cytoplasm. 



In section the nuclei show, to a very marked degree, the irregular 

 pointed processes along their outer border. In many places the mem- 

 brane is quite difficult to distinguish, being lost in the adjacent cyto- 

 plasm; this is especially true in those nuclei along whose outer border 

 the dark cytoplasmic areas are numerous. 



In surtace view (Fig. 18) many of the nuclei display a marked 

 contrast to what we have heretofore seen; in them the nucléoles have 

 generally lost their rounded outline and have become more elongated. 

 We find this most noticeable in the thinner regions of the nuclei, 

 where the nucléoles often appear as if they were being carried through 

 the narrow pai't. Many of the nuclei appear at this stage as if they 

 were disintegrating; long projections are numerous, and, at many 

 points some have the appearance of being broken up into smaller 

 pieces. Our figure shows but part of a nucleus so that the contrast 

 between the rounded ends of the branches and the narrower portions 

 extending between them is not clearly seen. In a few places are 

 shown the narrow spindle shaped nucléoles and their arrangement as 

 if trying to pass from one part of the nucleus to another. 



An examination of our other sections, those taken from glands 

 of longer periods of activity, shows but few changes from what we 

 have just described; we observe, however, after the maximum period 

 of activity, two hundred and forty hours, a few changes which it will 

 be well to record. 



The cytoplasm in the glands of this maximum period of activity 

 (Fig. 19) has lost the inner layer in which the structure appears sim- 



