June. 1921.] KUWADA :— LONGITUDINAL SPLIT OF CHROMOSOMES 105 



him, kindly shown his excellent preparations of the root-tips of 



Vicia, upon which his paper of 1914 is based. 



New York, Oct. 12, 1920. 



Explanation of liie Plate II. 



All the figures are magnified to the same power ; drawn with the aid of an Abbe's 

 camera lucida, and Leitz's achromatic immersion lens 1/16'/ and Spencer's ocular 10 

 are used for the study. Figs, i — 5 and Figs. 7 — 10 are from root-tips of FzV/rtr J^ada and 

 Fig, 6 from Professor Wilson's preparation of Phrynotettix. 



Fig. I, A nucleus in telophase showing vacuolization of chromosomes. Fixed for 

 24 hours. 



Fig. 2. A piece of a nucleus in telophase. Fixed for 12 liours. 



Fig. 3- The same in a little later stage. Fixed for 12 hours. 



Fig. 4. A nucleus in early prophase showing development of new chromosomes. 

 Fixed for 24 hours. 



Fig. 5. The same. Fixed for 24 hours. 



Fig. 6. A nucleus in early prophase of Spermatogonial division of Phrynotettix 

 showing development of a new chromosome. 



Fig. 7. A nucleus in a little later prophase, where anastomoses between chromo- 

 somes almost disappear leaving a small remnant in the upper part of the figure. 

 Fixed for 12 hours. 



Fig. 8. A nucleus in a later stage of prophase showing spiral aspect of new 

 chromosomes. Fixed for 24 hours. 



Fig. 9. A nucleus in a much later stage of prophase showing a sign of longitudinal 

 splitting of new chromosomes in a few places. Fixed for 24 hours. 



Fig. 10. A nucleus in a much advanced stage of prophase showing longitudinal 

 splitting of the chromosomes very clearly. Fixed for 24 hours. 



