450 BENJAMIN H. PRATT AND J. A. LONG 



THE DIPLOTENE STAGE 



Nuclei in the diplotene stage may first be distinguished at the 

 time of birth, or possibly a little earlier, and persist in com- 

 paratively large numbers for a couple of days thereafter. At 

 three days after birth they are but infrequently met with, prac- 

 tically all of the nuclei having passed over into the stage char- 

 acteristic of the early period of growth and designated by Wini- 

 warter as 'Noyoux dictye.' The early diplotene nuclei (figs. 16 

 and 17) show numerous contorted threads, more or less irregular 

 in outline, but often distinctly parallel in arrangement or wound 

 about each other in spirals. Fine strands of linin are often dis- 

 tinctly visible passing from thread to thread. The number of 

 individual threads is clearly greater than in the pachytene stage, 

 though the exact relations in this respect could not be definitely 

 determined . The diplotene threads are also clearly only about half 

 as wide as those of the previous stage. The orientation, so con- 

 spicuous in the threads of synaptene and pachytene nuclei, is 

 almost entirely lost. A large chromatin body is present in each 

 of these nuclei, and very often an additional one or two may 

 be discovered. The chromatin threads very commonly are 

 united to the chromatin body in large numbers (fig. 16). Some 

 of the threads are always connected with these bodies. It seems 

 from an examination of a large number of these diplotene nuclei, 

 that the individual threads are formed by a longitudinal splitting 

 of the pachytene threads, and that the chromatin is rapidly being 

 assembled in the large chromatin bodies. The appearance of 

 the later phases of the diplotene stage gives further evidence of 

 the validity of these inferences: the individual threads are no 

 longer distinctly visible as such; often rows of granules indicate 

 their probable former course; the linin may still be apparent, in 

 arrangement strongly suggesting the course of the former threads. 

 The chromatin bodies, chromatin nucleoli, are more definite in 

 outline and typically number one to three. These later stages 

 gradate imperceptibly into the nuclei characteristic of the early 

 growth period. 



