004 JORDAN. [Vol. VIII. 



abrupt one. It seems likely that the vesicle remains for some- 

 time on the verge of dissolution, and that the shock of separa- 

 tion from the ovary precipitates the sudden change. All the 

 eo-o-s that I have found, both in the body-cavity and in the 

 oviducts, contain a completely formed spindle. 



It is manifest, then, that in Dicmyctylus, at about the time 

 the egg falls from the ovary into the body-cavity, the greater 

 part of the germinal vesicle is distributed throughout the yolk. 

 With a high power (Zeiss, 2 mm. immersion) the debris of 

 the vesicle can be easily recognized surrounding the matura- 

 tion spindle near the upper pole of the q^%. The semi-fluid 

 nuclear sap containing minute granules lies between the yolk 

 spheres, and in it are strewn fragments of half -digested nucleoli. 

 In some cases a portion of the vesicular substance appears to 

 ooze out upon the surface of the Q.^g, where it has been de- 

 scribed as the perivitellin by Hertwig, Schultze, and others. 

 The perivitellin of the newt resembles the perivitellin of 

 Siredon, as figured by Schultze (see Schultze, '87, Fig. 29). 

 Schultze also recognized the remains of the nucleoli, — "kleine, 

 kreisrunde Chromatinkorperchen, offenbar die Reste der nicht 

 vollig gelosten Keimkorperchen." 



This admitted fate of a portion of the nucleolar substance 

 seems to me to indicate the fate of all. It does not appear to 

 me probable that, as Schultze maintains, a part of the material 

 of the nucleoli goes to form chromosomes while another part 

 degenerates and is lost, but rather that all the nucleolar sub- 

 stance shares alike. Dissolution and dissipation seems the 

 likely end of all the nucleoli, as it is here unquestionably the 

 end of some. 



Besides the disintegration of the vesicle, when the egg is 

 loosed from the ovary, there is another highly important but 

 very obscure change. This is the transformation of the chro- 

 mosomes from numerous, long, thin, faintly staining threads to 

 a few stout rods (Fig. 18). I have not been able to discover 

 how this welding of the chromosomic substance takes place. 

 The change from the delicate filamentous structure to the 

 massive compact one is apparently the work of a short time. 

 There seems to be a reduction in the number of individual 



