917 



Fig. 5. Upper part of the nucleus, showing its long, slender neck, and the site of 

 the embryo-sac previous to fecundation. 



Fig. 6. Apex of the nucleus, 240 times magnified. 



Fig. 7. Ovule, partly dissected to show the nucleus, 10 times magnified. 



Fig. 8. Nucleus after fecundation, 10 times magnified, a. Pollen-tube. b. Ca- 

 vity at base of the neck of the nucleus, c. Embryo-sac. 



Fig. 9. Neck of nucleus, 40 times magnified. Fig. 10. Apex of the same, 240 

 times magnified. 



Fig. 11. Apex of another nucleus, equally magnified, a. Pollen-tube inserted 

 therein. The tissue of the apex of nucleus, unbroken before fecunda- 

 tion (fig. fi) is now much divided. 



Fig. 12. Upper part of another nucleus, a longitudinal section, showing the ca- 

 vity in the neck, 10 times magnified. 



Fig. 13. Neck of nucleus more advanced (after fecundation), 10 times magnified. 

 a. Lower extremity of the supposed pollen-tube. The parts (40 times 

 magnified), are more distinctly seen at fig. 14. 



Fig. 15. Another example ; more magnified at fig. 16. 



Fig. 17. Another, still more advanced. Fig. 18. The same, 240 times magnified. 

 a. Embryo-sac. 



Fig. 19. Embryo-sac detached from the last example, 240 times magnified. 



Fig. 20. Another example, after fecundation. 



Fig. 21. Embryo-sac, from the last (10 times magnified), showing at (a) what ap- 

 pears to be the extremity of the pollen-tube. 



Fig. 22. Another ; the base more highly magnified at fig. 23. 



Fig. 24. Section of nucleus, more advanced, 10 times magnified, the lax tissue 

 which surrounds the embryo-sac displaced to show the embryo-sac and 

 its contents : this part is more highly magnified at fig. 25. 



Fig. 26. Upper part of ovule, several days after impregnation, dissected to show 

 (at a) the embryo seen detached at fig. 27. 



Fig. 28. Extremity of pollen-tube (or embryo-sac .^), as seen several days after 

 fecundation, and at a later stage than the one represented at fig. 14, 

 240 times magnified. 



Fig. 29. Pollen-grain, with its tube (240 times magnified) with its narrowed lower 

 extremity {b) at the distance of six diameters of the pollen-grain, 

 where it was broken off or discontinued. 



Fig. 30. Pollen-tube, as found opposite to the ovarium, with cellules of stigmatic 

 tissue attached to its surface, 240 times magnified. 



Fig. 31. Pollen-tube in the vicinity of the ovules, b. A tube of vascular tissue. 



Fig. 32. Nucleus from an advanced ovule (10 times magnified), showing the 

 neck lengthened out into a tube, beyond the foramen of the ovule. 



Fig. 33. Upper extremity of the last dissection, 45 times magnified. 



Fig. 34. Ditto 240 times magnified, showing the cul-de-sac termination above 

 (at a). 



Fig. 35. Ditto still further dissected, the tube cut through without much dis- 

 placement of its grumous contents. 



Fig. 36. Ovule, with two supposed pollen-tubes inserted into the foramen, 45 

 times magnified. 



Fig. 37. Upper part of the same, 240 times magnified. 



Vol. II. 5 y 



