262 
Campbell.— On the development 
Fig. 21. Free spermatozoids, a from above, b from the side ; colored with iodide 
of potassium, v, the vesicle with the included starch-grains, c, alcohol-gentian- 
violet-preparation. d , a vesicle from which the spermatozoid has become free. 
Leitz oil-immersion, . 
Fig. 22. a, Longitudinal section through an ungerminated macrospore, x 90. 
b, The nucleus of the same examined with a oil-immersion. Alcohol-gentian- 
violet-preparation. 
Fig. 23. A section through the wall of the macrospore, x 300. Alcohol- 
safranin-preparation. 
Fig. 24. Longitudinal section through a macrospore 4 \ hours after being placed 
in water. Flemming’s mixture-haematoxylin-preparation. 
Fig. 25. The nucleus of a spore of the same age, but colored with safranin and 
examined with a tV oil-immersion. 
Fig. 26. Two sections through a spore 16 \ hours after the commencement of 
germination, x about 100. Alcohol-haematoxylin-preparation. 
Fig. 27. The first wall is completely formed. In a is shown the nucleus of the 
mother cell of the prothallium, in b that of the spore. 
Figs. 27-32. Successive stages in the development of the female prothallium 
and archegonium, x 300. a, the first wall, b, the second wall, c, the primary 
canal-cell. Figs. 27, 31, 32, alcohol-gentian- violet-preparations ; Fig. 28, alcohol- 
safranin ; Fig. 29, Flemming’s mixture-safranin ; Fig. 30, chromic acid-safranin. 
Fig. 27, 19^ hours ; Fig. 32, 41 1 hours from the beginning of germination. 
Fig- 33. Cross-section of a prothallium 24 hours old. c , mother-cell of the 
archegonium. p, p' , peripheral cells. Alcohol-gentian- violet-preparation, x 300. 
Fig. 34. A similar section to Fig. 33, but somewhat further advanced. 
Fig- 35. Cross-section of the basal part of a young prothallium. The succession 
of the walls is indicated by the numbers. Alcohol-gentian-violet-preparation, 
x 300. 
Fig. 36. A similar section from a full-grown prothallium. Alcohol-Bismarck- 
brown-preparation. 
Fig. 37. A section through the neck of a full-grown archegonium. Alcohol- 
Bismarck-brown-preparation. x 300. 
Figs. 38, 39. Sections through archegonia in which fertilization has recently 
taken place. Fig. 38 a longitudinal, Fig. 39 cross-section, sp, the male nucleus. 
In Fig. 38 several spermatozoids are seen about the neck of the archegonium. 
Alcohol-gentian-violet-preparation, x 300. 
PLATE XIV. 
Fig. 1. Transverse section of the fertilized germ-cell undergoing the first division. 
Alcohol-safranin-preparation. x 300. 
Fig. 2. Longitudinal .section of a somewhat more advanced stage, in which the 
first division is complete. This and the succeeding figures, unless otherwise stated, 
were drawn from preparations fixed with absolute alcohol, and colored with 
gentian-violet, and magnified 300 diameters. 
