No. 2.] THE DEVELOPMENT OF THE NEWT. 289 



Staining fluids (Fig. 10, PI. XV). Whether or not these conden- 

 sations are the immediate progenitors of such undoubted yolk- 

 nuclei as that represented in Fig. 11, I am unable to decide, 

 but it seems to me highly probable that such is the case. 

 Between the latter and such complex bodies as that shown in 

 Fig. 13, PL XV. are found all gradations. I think it exceedingly 

 probable that in the newt the yolk-nuclei always arise first as 

 condensations of the cytoplasm and subsequently increase in 

 size and complexity with the growth of the ^gg} 



At first they lie about half-way between the germinal vesicle 

 and the periphery of the Q<gg and often maintain this relative 

 position for some time, but eventually they draw nearer to the 

 germinal vesicle and in large eggs are usually found in close 

 contact with it. It is not unlikely that they sometimes fuse 

 with the substance of the vesicle, but from sections it is of 

 course impossible to obtain absolute proof of complete fusion. 

 Certainly a more common fate would seem to be the gradual 

 disintegration of these bodies and the dispersion of the derived 

 granules around the germinal vesicle in the manner described 

 by Cramer ('48) and Schultze ('87). This breaking up of the 

 yolk-nuclei appears to be their ordinary fate, and I have often 

 observed such a disintegration as is figured by Schultze ('8?) in 

 Figs. 4«, j\b, 4c, Afd. As the yolk-nuclei approach the stage at 

 which this resolution into granules takes place, they generally 

 assume a somewhat complex structure. They become more 

 sharply marked off from the surrounding yolk (Figs. 10, 11, 12 

 and 13, PL XV), and are usually differentiated into two elements, 

 a coarsely granular portion staining feebly and resembling 

 ordinary cell protoplasm, and a more compact portion of vary- 

 ing extent which stains deeply with carmine or alum cochineal. 

 This highly stainable constituent often occurs irregularly dis- 

 posed in two or more patches in a single yolk-nucleus as in Fig. 

 13, PL XV, and Fig. 16, PL XVI. This fact might perhaps be 

 thought to countenance the view that these large yolk-nuclei 

 arise from the union of several of the smaller bodies, but it is 



1 1 have never seen anything that would indicate that the yolk-nucleus arises 

 from a large nucleolus which has migrated mto the cytoplasm in the manner de- 

 scribed by Will, and on this point am in full accord with Stuhlmann ('86). 



