726 
Beer . — Studies in Spore Development. II. 
Fig. 33, a and b. Matricaria Chamomilla. a. Telophase of heterotype division, b. Inter- 
kinesis. x 1,900. 
Fig. 34. Crepis taraxacifolia. Telophase with median vacuolization of chromosomes, x 1,500. 
Fig. 35. Tragopogon pratensis. Telophase with diffuse vacuolization of chromosomes, x 2,600. 
Figs. 36 and 37. Tragopogon pratensis. Interkinesis. Fig. 36 x 2,600; Fig. 37 x 1,500. 
Fig. 38. Matricaria Chamomilla. Metaphase of homotype division, x 1,900. 
Fig. 39. Matricaria Chamomilla. Telophase of homotype division, x 1,900. 
Fig. 40, a-d. Matricaria Chamomilla . Four successive stages of homotype telophase, d is 
from a young pollen-grain with its own wall round it. x 1,900. 
Fig. 41, a and b. Matricaria Chamomilla. Nuclei from young pollen-grains. 41 a is from 
a pollen-grain of approximately the same stage as 40 d. x 1,900. 
Fig. 42. Crepis taraxacifolia. Homotype division. Concentration of chromosomes in two 
longitudinal halves, x 1,900. 
Fig. 43. Tragopogon pratensis . Homotype division. Concentration of chromosomes as 
undivided bands of chromatin, x 2,600. 
Fig. 44. Crepis taraxacifolia. Homotype division. Spireme, x 1,900. 
Fig. 45. Crepis taraxacifolia. Homotype division. Spireme. Chromosome segments distinct, 
x 2,600. 
Fig. 46. Crepis taraxacifolia. Homotype division. Spireme, x 1,500. 
Fig. 47. Tragopogon pratensis. Homotype division. Chromosomes on equator of spindle, 
x 2,600. 
Fig. 48. Crepis taraxacifolia. Homotype division. Metaphase, x 2,600. 
Fig. 49. Crepis virens. Homotype division. Early anaphase, x 2,600. 
Figs. 50 and 51. Tragopogon pratensis. Homotype division. Two successive stages of the 
anaphase, x 2,600. 
Figs. 52. Crepis virens. Homotype division. Late anaphase, x 2,600. 
Figs. 53, 54, and 55. Telophase of homotype division in Tragopogon pratensis, Crepis taraxaci- 
folia , and C. virens respectively. Central vacuolization of chromosomes. Fig. 53 x 1,900 ; 
Figs. 54 and 55 x 2,600. 
Figs. 56, 57, and 58. Crepis taraxacifolia. Homotype division. Telophase. Chromatin 
droplets in cytoplasm, x about 2,000. 
Fig* 59. Crepis taraxacifolia. Two nuclei from very young pollen-grains (still united in the 
tetrad), x 1,900. 
Fig. 60. Crepis virens. Homotype division. Telophase. Chromatin droplet passing into 
the cytoplasm, x 1,900. 
Fig. 61. Resting nucleus from anther wall, x 2,600. 
Fig. 62. Prophase. Concentration of chromosomes in two halves, x 2,600. 
Fig. 63. Prophase in Crepis taraxacifolia. Concentration of chromosomes as single, undivided 
bands, x 2,600. 
Fig. 64. Prophase. ‘ Corkscrew ’ spireme, x 2,600. 
Fig. 65. Spireme concentrating in two longitudinal halves. Anther wall, x 2,600. 
Fig. 66, a and b. Spireme longitudinally divided, x 2,600. 
Fig. 67. Prophase of premeiotic division in an archesporial cell. Polarization of parts is to be 
noted, x 2,600. 
Fig. 68. Metaphase. Two long chromosomes, tw'o short ones, and two of intermediate size 
occur in this nucleus, x 2,600. 
Fig. 69. Metaphase. Six chromosomes from another nucleus, x 2,600. 
Fig. 70, a and b. Two stages of the anaphase, x 2,600. 
Fig. 71. The two daughter nuclei in telophase, x 2,600. 
Fig. 72. Daughter chromosomes in telophase, x 2,600. 
Fig* 73 * Conclusion of telophase. Daughter nuclei passing into ‘resting’ state, x 2,600. 
Fig. 74. Portion of pollen-grain of Matricaria Chamomilla (Tubuliflorae). x 1,900. 
Fig. 75. Pollen -grain of Tragopogon pratensis (Liguliflorae). x 1,500. 
Fig. 76. Pollen-grain of Artemisia vulgaris (Tubuliflorae), with smooth, unfolded exospore, 
x 1,100. 
Fig. 77. ‘Resting’ nucleus from the anther wall of Calendula, x 1,900. 
