28o The Ohio Naturalist. [Vol. VIII, No. 5, 



granule is still clearly visible showing in addition to a few short 

 rays stretching away from the nucleus others connecting with 

 the nuclear membrane. 



The various irregularities in the centrosomes are to be com- 

 pared in the judgment of the writer, to those present in the for- 

 mation of centrosomes de novo, under more or less abnormal 

 chemical stimulation, in animals. In many of these cases there 

 are formed a multitude of small asters two of which grovv large 

 and form the amphiaster. Because of the difficulty of deter- 

 mining the sequence of events, having no other indications of 

 the relative ages beside the condition of the asters themselves, 

 it cannot be asserted that the different asters coalesce or that one' 

 of them gains the mastery while the other disintegrates. Never- 

 theless it is to be noted that without exception those asters which 

 are interpreted as the end stages were, so far as seen, uniformlv 

 single (figs. 12-14). 



The activities of the centrosomes and of the chromatin in the 

 reconstruction of the nucleus are apparently independent of each 

 other to a considerable degree so that it seems necessary to con- 

 sider them separately. In the telophase the four chromosomes 

 lie loosely in the cytoplasm making a figure not unlike the typical 

 daughter star. They have a manifest tendency to converge to 

 the centrosome which is more clearly shown in cases where there 

 are two asters, when part of the chromosomes may follow the rays 

 of each. At the distal ends of the chromosomes, with respect ot 

 the aster, there soon appears, in connection with one or more of 

 them (fig. 2) a thickening which enlarges at the expense of the 

 chromosomes till it becomes the karyosome (nucleolus) of the 

 resting nucleus (fig. 2). The transfer of the chromatin to the 

 karyosome consists apparently, not so much in the direct absorp- 

 tion of the chromosomes as in the gradual removal of the chro- 

 matin from the linin matrix so that in many cases the ends of the 

 chromosomes farthest away from the karyosome become vacuo- 

 late, as it were, and lose their staining reaction giving a gradual 

 transition from one condition to the other thereby showing ap- 

 parently that the chromatin migrates granule by granule from 

 the linin matrix (fig. 2.) Those chromosomes wliich do not di- 

 rectly connect with the growing karyosome form linin l)ridges 

 across to it, by which the chromatin may be transferred. 



In many cases the nuclear membrane is formed before this 

 process is complete and there results a spirem which closely re- 

 sembles that usually found in the prophase of dividing cells, 

 (figs. 7-11). In such spirems all resemblance to the original 

 chromosomes may be lost and a loose, few-meshed network 

 formed. In as much as the conduct of the chromatin and of the 

 asters are independent, some doubt is thrown on the exact se- 

 quence of the trnncformntions of tlie nucleus as well as of the cen- 



