Figs. G5-()7. Three nuclei from the bladder of cat, showing degrees of 

 shortening of the contracted nucleus. Zenker''s fluid. Iron-hrematoxyliu. 

 X 3000. 



Figs. 68-72. Nuclear contraction in the muscular stomach of chickens. Fig. 

 08 shows a resting nucleus. The remaining figures show the changes in 

 shape and the arrangement of the chromatin at various phases of contrac- 

 tion. Zenker's fluid. Iron-htematoxylin. x 3000. 



Figs. 73-76. Stages in the contraction of the nucleus in the muscular 

 stomach of a 14-day chick embryo. There is during contraction a decrease 

 in length. There are few chromatin changes. Zenker's fluid. Iron-ha:»ma- 

 toxylin. x 2200. 



Figs. 77-84. Nuclear contraction phases in the carotid of ox. Fig. 77 

 shows a resting nucleus. Figs. 78-80 show shortening and thickening of the 

 nuclei. Figs. 81-84 show folding or spiral winding of the nucleus which may 

 possibly be typical at times for arterial nuclei. Figs. 81, 82, along with 

 coiling, have also undergone shortening and thickening. Zenker's fluid. Iron- 

 hjiematoxylin. x 3000. 



