No. 3-] THALASSEMA AND ZIRPHAEA. 617 



with Auerbach's fluid, a uniform bluish green, sometimes almost 

 as brilliant as that of the nuclei. As the egg increases in size 

 and protrudes into the lumen of the tubule, the cytoplasm takes 

 the fuchsin in increasing quantity and assumes more and more 

 of a reddish tint. This ultimately predominates over the green, 

 and by the time the egg has broken away from the wall of 

 the tubule the green is scarcely noticeable. Iron haematoxy- 

 lin, followed by orange or other plasma stain, gives a similar 

 result ; the cytoplasm, which in early stages takes the haema- 

 toxylin intensely, shows with growth a steady increase in its 

 affinity for orange. These changes can hardly be due to expul- 

 sion of nuclear elements into the cytoplasm, for all elements 

 within the nucleus show a steady growth and differentiation. 

 The chromosomes and nucleolus increase in size, and the latter 

 in complexity, while pari passu the formerly sparse and scat- 

 tered nuclear reticulum becomes close and compact, filling the 

 entire nucleus. Moreover, in some preparations, the base of 

 the growing egg showed a more marked affinity for the nuclear 

 stains than did the cytoplasm near the nucleus. These points, 

 taken in connection with the behavior of the free nuclei, point 

 to the latter as being the active agent in elaborating cyto- 

 plasmic material. 



When full grown, the ovum is but half the diameter {viz., 

 40ft) of that of Thalassema. Its close and dense cytoplas- 

 mic reticulum, in whose meshes the fine granular yolk is dis- 

 tributed, renders the egg excessively opaque. The asters and 

 spindles do not, in consequence, show as brilliantly as in TJial- 

 assevia, while the centrosome is often lost to view among the 

 innumerable granules that fill the egg. The germinal vesicle 

 is quite eccentric and filled by a close reticulum. The comple.x 

 double nucleolus (PL XXXIV, Fig. 47), characteristic of Lame! 

 libranchs and some vertebrates (Flemming, '82), some annt 

 lids (Wilson, '96) and invertebrate liver cells (Lomberg, '92), 

 here shows to advantage. The smaller portion (" Haupttheil" 

 of Flemming) stains black with haematoxylin and green with 

 Auerbach's fluid. Generally hemispherical in outline, it sits 

 like a cap upon the larger vesicular " Nebentheil" (Flemming). 

 It is, however, sometimes apparently spherical, or even bi- or 



