The early development of Eudendriiira. 267 



among which there has apparently been from the first a coarse, cyto- 

 plasmic reticulum as shown in Fig. 21. At certain regions of this 

 reticulum this proliferation of nuclei seems to be more active than 

 elsewhere, as shown in Figs. 17—20 where they form nest-like clusters 

 within which later occurs definite cell organization. Such a nest is 

 shown in Fig. 22. 



An examination and comparison of several of the figures cited 

 would seem to indicate something like a migration of the nuclei from 

 place to place, where following later multiplication, they become 

 centers of more or less active metabolism, involving the disintegration 

 of the yolk-masses and their direct transformation into a proteid sub- 

 stance more easily available by the growing cells. By means of 

 various differential staining it was possible to trace in more or less- 

 detail the progress of this metabolism which beginning with the 

 peripheral yolk spheres gradually extended toward the center till the 

 entire mass was disintegrated and liquefied. At first these yolk spheres 

 always took a very deep stain with any of the hematoxylins used, 

 with Heidenhain's they became densely black. Following their dis- 

 integration the staining properties became much less intense, or wholly 

 different. 



Am it OS is. It should be remarked in this connection that while 

 in the very early cleavage phases coincident with the yolk cleavage 

 and probably in some way associated therewith as shown in Figs. 24 

 and 25 there were abundant mitoses, yet in the later stages, parti- 

 cularly those involving the apparent migration of nuclei and their multi- 

 plication within the yolk-masses they seem to be conspicuously lacking. 

 The syncytial character of the early embryo has already been referred 

 to. During this period, specially in its earlier history, the nuclei 

 differed greatly both in size and shape. Some were many times larger 

 than others, while adjacent nuclear nests often showed indications of 

 having resulted from the amitotic division of a larger nucleus. Again, 

 many nuclei in their elongated and dum-bell shapes also suggested 

 strongly phases in amitosis, as shown in Fig. 23 a, b. Another interesting 

 and suggestive fact in this connection is the occurrence of string-like 

 series of nuclei along, or within, threads or strands of the cytoplasmic 

 reticulum, as shown in Fig. 21. 



It need hardly be stated that this condition was found under the 

 most varied methods of fixation and staining, both from preparations 

 stained in toto and on the slide, and by subsequent decolorization 

 and the application of an entirely different stain. 



