180 Harry Lewis Wieman. 



of the spireme can now be made out very distinctly, and the bi- 

 lobed body is seen at x. In Fig. 47 is shown a sHghtly older stage in 

 which the chromatin is collected in knot-like aggregations that man- 

 ifest a diminishing tendency to unite with the basic dye, while the 

 odd body or chromatin nucleolus, as it now maybe called, retains its 

 basic-staining capacity and becomes more prominent by contrast. 



In Fig. 48, a reticular structure can be made out, at the nodal 

 points of which can be seen small collections of chromatic material. 

 Fig. 49 marks the end of the resting stage and shows the reticulum 

 very jagged and irregular. It will be noticed that the nucleolus 

 is attached to the ends of two parallel threads, and this is the first 

 step in the reconstruction of the spireme of the prophase of the 

 first maturation divison. In Figs. 50 and 51, this spireme is seen 

 to be composed of two homologous parts, each containing the 

 reduced number of segments. From its position in close contact 

 with the nuclear membrane, the nucleolus of the resting stage {x) 

 can be readily distinguished from the segments of the spireme 

 which it greatly resembles, (Fig. 50.) In Fig. 51, its identity is not 

 so certain. Figs. 52 and 53 are prophases in which the spireme is 

 breaking up into the reduced number of bivalent chromosomes 

 plus the nucleolus, resulting in the production of seventeen bodies, 

 each showing a transverse constriction. All except the nucleolus 

 soon show the presence of another constriction at right angles 

 to the first, forming the tetrads of Fig. 53. Here the nucleolus 

 or odd body is shown in its characteristic position even before 

 the spireme has completely segmented. It shows nothing of the 

 quadri-partite condition of the other chromosomes that is indica- 

 tive of the two subsequent maturation divisions. 



The succeeding stages (Figs. 54, 55, and 56) have already been 

 described. In Figs. 59 and 60 are shown the metaphases of the 

 second division. In the former, seventeen chromosomes, including 

 the odd body, {x) are represented, and in the latter, sixteen. No 

 anaphases sufficiently clear for counting or drawing were found, 

 but it is evident from Fig. 58 which is a characteristic second 

 division telophase, that no uneven distribution of the chromo- 

 somes takes place, so that it is inferred that the bi-partite body 

 divides, either transversely or longitudinally. 



