542 Cannon : Studies in Plant Hybrids : 



Plate 17 



Figs. 1-3. Fillbasket, pure race. Anaphase of last sporogenous division ; pairing 

 of the chromosomes not well marked. The three sketches were made from one nucleus. 



Fig. 4. Fillbasket, pure race. Late anaphase of the last sporogenous division. 

 The chromosomes are uniting in pairs. One chromosome is in the section next to the 

 one from which the sketch was made. 



Fig. 5. Fillbasket X Debarbieux. Nuclear plate of the last sporogenous division. 

 Six chromosomes are associated in pairs. 



Fig. 6. Fillbasket X Debarbieux. Anaphase of last sporogenous division showing 

 a pairing of the chromosomes. 



Fig. 7. Fillbasket X Debarbieux. Early reconstruction stage in last sporogenous 

 division, showing the fusing of the pairs of chromosomes at their polar ends ; three 

 chromosomes are in the adjoining section. The connecting chromatin is exaggerated in 



the sketch. 



Fig. 8. Fillbasket X Debarbieux. Same division as the preceding ; the connect- 

 ing ring of chromatin does not become reticulated as early as the remainder of the 

 chromosomes. 



Fig. 9. Fillbasket X Debarbieux. Same division as the preceding sketch ; shows 

 fusing of chromosomes at the polar ends. 



Figs. 10-14. Fillbasket X Debarbieux. Figs. 10-12 are sketches of metaphase 

 of sporogenous division, />ro^ad/y noi the last one, and figs. 13 and 14 are anaphases 

 of two similar divisions. These do not show pairing of the chromosomes. 



Plate 18 



Figs. 15-17. Express X Serpette. Prophase of the first maturation mitosis, het- 



erotype rings. 



Figs. 18, 19. Fillbasket X Debarbieux. Metaphase of the first maturation 



division. 



Fig. 20. Fillbasket X Debarbieux. Chromosomes from the metaphase of the first 



division. 



Fig. 21. Fillbasket X Debarbieux. Nuclear plate, first division, showing the re- 

 duced number, seven, of chromosomes. 



Figs. 22, 23. Fillbasket X Debarbieux. Anaphase of the first maturation mitosis ; 

 in the latter sketch one of the chromosomes has failed to divide ; this was the only 

 abnormality which was seen in the sporogeny of the pea hybrids. 



Figs. 24, 25. Fillbasket X Debarbieux. All of the chromosomes of one daughter 

 nucleus are shown ; the number of chromosomes is seven. 



Fig. 26. Fillbasket X Debarbieux. Early reconstruction stage of a daughter 

 nucleus ; one chromosome is in the adjoining section. No splitting of the segments is 

 to be seen. 



Fig. 27. Fillbasket X Debarbieux. Metaphase of the second maturation di- 

 vision. 



Fig. 28. Fillbasket X Debarbieux. Typical chromosomes from the metaphase of 

 the second division. 



Figs. 29, 30. Fillbasket X Debarbieux. Metaphase of the'second division show- 

 ing the reduced number of chromosomes to be even ; the nuclei are sister nuclei. 



Fig. 31. Fillbasket X Debarbieux. Resting nucleus of tetrad; shows complete 

 resting condition. 



