FUNCTIONAL AND RUDIMENTARY SPERMATOZOA. 327 



(diluted i : i) was allowed to run under and to stain the cells for 

 about two minutes. This was then washed out with tap water. 

 All of these processes were carried on under the microscope in 

 order to make certain that no mistakes of indentification of these 

 cells should be made after the slides were finished. Although 

 this is a tedious method it has the advantage of being perfectly 

 reliable and furnishing accurate data concerning which there can 

 be no doubts. Many other methods were tried but none were 

 found to be as practical and as certain as this one. 



The nucleus was first indentified in an early stage of the normal 

 spermatid (Fig. i, A) which later would have developed into the 

 large motile spermatozoon (Fig. I, B}. 



The degenerate sperm cells from the same male individual 

 were examined next and each was found to contain a nucleus with 

 chromatin material in it. This stage is shown in Fig. 2, A. This 

 fact is of considerable interest because it demonstrates that in 

 the division that forms the secondary spermatocytes there is 

 evidently a division of the chromatin material and consequently 

 all the secondary spermatocytes contain some of this chromatin 

 material. One half of these secondary spermatocytes divide 

 and form the normal spermatids but the remaining half of the 

 secondary spermatocytes do not divide again but develop directly 

 into the degernerate spermatozoa. The early stage of these 

 degenerate spermatocyte cells are smaller in size than the normal 

 cells of the same age but the nucleus is only slightly smaller than 

 the nucleus contained in the normal spermatid cell as can be seen 

 by comparing Figs. 2, A and i, A. 



The later development of each of these two kinds of cells is 

 very different. In the normal cell the nucleus grows larger and 

 larger until in its final stage it is several times its former size. 

 From one end of the cell an outgrowth appears which grows longer 

 and longer and finally becomes vibratile. This is the motile tail 

 of the sperm cell. It is very long and large and has an undulating 

 membrane along the greater portion of the dorsal side. Fig. 

 I, B, shows the entire matured spermatozoon containing the 

 large mass of chromatin material in the head. 



The development of the smaller and degenerate spermatocyte 

 cells into the complete rudimentary spermatozoa is strikingly 



