No. 2.] THE EGG OF BUFO LENTIGINOSUS. 311 



are broken up into still smaller granules, which later fuse to 

 form the irregular masses found near the line of radiation. 

 This assumption is certainly correct if reactions towards stains 

 form any criterion on which to base a judgment of the nature 

 of a substance ; for when the nucleoplasm can again be distin- 

 guished as such by its light pink color, these bodies take the 

 deep carmine stain which is so characteristic of chromatin. I 

 can offer no explanation as to why the chromatin nucleoli 

 should be broken up into minute particles, and these particles 

 subsequently reunited into large masses. 



The processes which Osterhaut ('97) describes as leading to 

 the formation of the karyokinetic spindle in the spore-mother 

 cells of Equisetum bear a striking resemblance to the changes 

 occurring in the breaking down of the germinal vesicle in the 

 toad's Qgg. In Equisetum, when the chromatin skein is be- 

 ginning to break up into chromosomes, a layer of cytoplasm 

 lying close around the outside of the nucleus, the " Kinoplasm " 

 of Strasburger ('92), stains differently from the rest of the 

 trophoplasm and broadens apparently at its expense. The 

 kinoplasm first forms a fine meshwork, but soon changes to a 

 coarse, irregular reticulum, which contains a number of small 

 granules and forms a thick layer close to the nuclear wall. 

 The threads of this layer thicken, stain more deeply, and 

 arrange themselves at right angles to the nuclear membrane in 

 the form of a pronounced radiation which later extends up into 

 the nucleus and becomes the spindle. Osterhaut believes 

 that the kinoplasm is probably derived primarily from the 

 trophoplasm; but as the kinoplasm is not apparent in the 

 resting cell, he cannot tell whether or not it is a specific sub- 

 stance in the sense of Boveri's "archoplasm." 



At the stage of PI. XXIX, Fig. 17, with the exception of the 

 peculiar large nuclear bodies which appear during the hiberna- 

 tion period, and the small ones presumably composed of chro- 

 matin, all the nucleoli have changed into yellowish-green 

 refractive bodies and are going through the final processes of 

 disintegration. From the apparently normal form (PI. XXVIII, 

 Fig. 12, A) several small round portions are first separated off 

 (Fig. 12, B)\ the central part then breaks up (Fig. 12, C), and 



