CELL DIVISION IN T.ENIA. 315 



reticulum, blackish ; nuclear plasm, very light green ; general 

 cytoplasm, dark green, fibre-reticulated ; "Nebendotter," homog- 

 enous " cheesy " green. This last appearance is very difficult 

 to describe but is recognized very easily. 



The "Nebendotter" as such has not been described by Child. 

 One is compelled to suspect that the same appearances which 

 confused me may have misled him. Occasionally a constriction 

 is seen in a " Nebendotter" or there may be two or more distinct 

 yolk masses in a cell. More often, especially in the case of 

 haematoxylin slides not well decolorized, the "Nebendotter' 

 does not look unlike a dividing or divided half of the nucleus. 

 Child figures cases in which one half of the nucleus stains darker 

 than the other half. Is this darker half perhaps a " Nebendotter"? 



To illustrate the above facts a series of outline drawings is 

 given. They were made with the aid of a Zeiss No. 5 ocular and 

 a Leitz one twelfth objective (oil immersion). In each case n 

 represents the nucleus and y the " Nebendotter." In studying 

 these figures one can easily see how refractive properties may have 

 obscured the boundaries between the various parts. All figures 

 in this series are of resting cells such as are shown in Figs. I 

 and 2. Figs. 3 and 4 resemble cases of unequal constriction of the 

 nucleus, Fig. 8, of equal constriction, and Fig. 5 a nucleus divided 

 into three parts by amitosis. Fig. 6 suggests that division began 

 at the center and progressed outward. Compare these figures with 

 those from Child's paper on oogenesis (6) : Fig. I with his Fig. 

 29 ; Fig. 2 with his Fig. 9, b ; Fig. 3 with his Fig. 8, b ; Fig. 6 

 with his Fig. n, A, a; Fig. 7 with his Fig. 13, A; and Fig. 8 

 with his Fig. 10, A. The similarity is very suggestive. 



Resting nuclei are seen in Figs, i, 2, and 9. Fig. 9 is lacking 

 in a " Nebendotter." The nuclear plasm in the resting condition 

 seems homogeneous throughout and takes a very light stain. 

 The nuclear membrane is a very delicate structure, showing as 

 a thin line in some cases, while in others its location is marked 

 only by the inner edge of the cytoplasmic reticulum. A nucle- 

 olus is usually present in the early stages of cell formation ; it 

 takes a very light stain in some cases resembling the " Neben- 

 dotter." I have never seen a divided or dividing nucleolus. 



With regard to their chromatin content the nuclei of Tcenia 



