126 WILLIAM M. GOLDSMITH. 



some is llnin or closely related in composition to it. As the linin 

 and the achromatic body becomes continuous the latter is pulled 

 into various shapes and becomes practically indistinguishable 

 from the linin (Fig. 25). While these changes are taking place, 

 the peripheral areas of linin become more conspicuous the 

 larger number of these aggregations being either near or in con- 

 tact with the nuclear membrane. In order to form the chromo- 

 somes the linin collects, leaving wide intervening spaces almost 

 clear (Figs. 23-26). Usually in the formation of these aggrega- 

 tions, strands of linin connecting the centralized mass (the former 

 nucleolus) and the nuclear membrane remain in contact on one 

 side longer than on the other. Whether or not this action is 

 associated with the movement of the central mass to the vicinity 

 of the nuclear wall in early prophase, we can only surmise (Figs. 

 25 and 26). In the meantime the achromatic parts of the 

 nucleolus and the linin network, become more and more indis- 

 tinguishable from one another. 



As the aggregations of chromatin and linin become more 

 compact, in the formation of the bivalent chromosomes of the 

 first spermatocyte division (Figs. 28 to 30), masses and strands 

 of achromatin may be observed attached to the chromosomes 

 and floating in the cell sap (Fig. 27). This same condition is 

 figured by Stevens ('n) in the spermatocyte cells of the guinea 

 pig. She notes that "in early prophase the chromatin appears 

 as though gathering together about definite centers along the 

 spireme, leaving the linin threads between." However, the 

 chromosomes in the material under consideration, are so far 

 apart that the strands of linin are usually broken between them. 

 By this time, no discrimination can be made between the achro- 

 matic part of the former nucleolus and the linin, except in a few 

 cases where large collections of achromatic material is indicative 

 of the former (Fig. 28). 



DISCUSSION. 



It would be next to impossible to draw conclusions of general 

 application from the above observations, since they are based 

 upon only one species. It seems advisable, however, to call 

 attention to some of the important facts regarding the origin, 



