542 CANNON: SrupiEs In PLANT HysrIDs: 
PLATE 17 
Fics. 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. 
Fic. 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, 
Fic. 5. Fillbasket }< Debarbieux. Nuclear plate of the last sporogenous division. 
Six chromosomes are associated in pairs. 
Fic. 6. Fillbasket X Debarbieux. Anaphase of last sporogenous division showing 
a pairing of the chromosomes. 
Fic. 7. Fillbasket < 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. 
Fic. 8. Fillbasket % Debarbieux. Same division as the preceding; the connect- 
ing ring of chromatin does not become reticulated as early as the remainder of the 
chromosomes. 
Fic. 9. Fillbasket  Debarbieux. Same division as the preceding sketch ; shows 
fusing of chromosomes at the polar ends. 
Fics. to-14. Fillbasket < Debarbieux. Figs. 10-12 are sketches of metaphase 
of sporogenous division, probably not the last one, and figs. 13 and 14 are anaphases 
of two similar divisions. These do not show pairing of the chromosomes. 
PLATE 18 
Fics. 15-17. Express < Serpette. Prophase of the first maturation mitosis, het- 
erotype rings. 
Fics. 18, 19. Fillbasket  Debarbieux. Metaphase of the first maturation 
division. 
Fic, 20. Fillbasket )< Debarbieux. Chromosomes from the metaphase of the first 
division. 
Fic. 21. Fillbasket  Debarbieux. Nuclear plate, first division, showing the re- 
duced number, seven, of chromosomes. 
Figs. 22, 23. Fillbasket < 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. 
Fics. 24, 25. Fillbasket )< Debarbieux, All of the chromosomes of one daughter 
nucleus are shown ; the number of chromosomes is seven. 
Fic. 26. Fillbasket  Debarbieux. Early reconstruction stage of a daughter 
nucleus ; one chromosome is in the adjoining section, No splitting of the segments 15 
_ to be seen. : 
Fic. 27. Fillbasket < Debarbieux. Metaphase of the second maturation di- 
vision. 
Fic, 28. Fillbasket < Debarbieux. ‘Typical chromosomes from the metaphase of 
the second division. 
Fics. 29, 30. Fillbasket  Debarbieux. Metaphase of the second division show- 
ing the reduced number of chromosomes to be seven; the nuclei are sister nuclei- 
Fic. 31. Fillbasket < Debarbieux. Resting nucleus of tetrad; shows complete 
resting condition. 
