Beer. — -Studies in Spore Development. II. 
7 2 5 
EXPLANATION OF PLATES LXVI AND LXVII. 
Illustrating Mr. Beer’s paper on the Structure and Division of the Nuclei in the Compositae. 
All figures were drawn with the aid of the camera lucida. Either Zeiss’s apochrom. objective 
2 mm. (aper. 1.40) or Leitz’s inch objective was used with various compensating oculars. 
Figs. 1-37 refer to the heterotype division. 
Figs. 38-60 refer to the homotype division. 
Figs. 61-73 refer to the somatic divisions of Crepis virens } with the exception of Fig. 63, which 
represents the somatic division of C. taraxacifoiia. 
Fig. 1, a and b. Doronicum plantagineum. Nuclei during presynapsis, a. Nucleus seen in section. 
b. Nucleus in surface view, x 2,600. 
Fig. 2. Doronicum plantagineum. Nucleus shortly before synaptic contraction, x 1,900. 
Fig. 3. Tragopogon pratensis. Nucleus previous to synapsis, x 2,600. 
Fig. 4, a and b. Calendula officinalis. Nuclei previous to synapsis, x 2,000. 
Fig. 5. Calendula officinalis. Early synapsis, x 2,000. 
Fig. 6. Doronicum plantagineum . Synapsis, x 2,600. 
Fig. 7. Doronicum plantagineum. Synapsis, with a rather looser coil than in Fig. 6. x 2,600. 
Fig. 8. Calendula officinalis. Synapsis ; later stage, x 1,900. 
Fig. 9. Calendula officinalis. Portion of spireme showing chromomeres. x 2,600. 
Fig. 10, a and b. Crepis taraxacifoiia. Hollow spireme, x 2,600. 
Fig. 11. Matricaria Chamomilla. Unfolding of synaptic coil, x 1900. 
Fig. 12. Crepis taraxacifoiia. Second contraction, x 2,600. 
Fig. 13. Crepis taraxacifoiia. Second contraction. Sides of loops rather near together and 
ends of loops out of the field of vision, x 2,600. 
Fig. 14. Crepis taraxacifoiia. Second contraction. Sides of loops have become closely 
approximated, and the long, bent loops give the impression of a longitudinally divided spireme, 
x 1,900. 
Fig. 15. Crepis taraxacifoiia. Single loop of second contraction with closely approximated 
sides, x 2,600. 
Fig. 16, a and b. Tragopogon pratensis. Second contraction, x 1,500. 
Fig. 17. Tragopogon pratensis. Second contraction. Sides of loops approximated and their 
ends not in field of vision, x 1,500. 
Fig. 18. Matricaria Chamomilla. Second contraction, x 1,500. 
Fig. 19. Matricaria Chamomilla. Loops (= bivalent chromosomes) separating from their 
common meeting point. X 2,600. 
Fig. 20. Tragopogon pratensis. Loops (= bivalent chromosomes) soon after they reach the 
periphery of the nucleus, x 1,500. 
Fig. 21. Crepis taraxacifoiia. Single loop (= bivalent chromosome) in which the closed end 
of the loop is just breaking across. The arms of the loop ( = univalent chromosomes) joined by 
delicate chromatic processes. N ucleus at about the same stage as that shown in Fig. 20. x 2,600. 
Fig. 22. Crepis taraxacifoiia. Two bivalent chromosomes during diakinesis. x 2,600. 
Fig. 23. Matricaria Chamomilla. Diakinesis. The chromosomes have all assumed the form 
of rings which are joined together by delicate filaments, x 1,900. 
Fig. 24. Tragopogon pratensis. Multipolar spindle with six chromosomes upon it. x 2,600. 
Fig. 25. Tragopogon pratensis. The six chromosomes during metaphase, x 2,600. 
Fig. 26. Matricaria Chamomilla. Commencement of anaphase. The regular form of these 
chromosomes is to be noted, x 1,900. 
Figs. 2 7 and 28. Matricaria Chamomilla. Two stages of the anaphase, x 1,900. 
Figs. 29 and 30, a and b. Tragopogon pratensis. Commencement of anaphase and a late 
stage of the same respectively. Fig. 30 b shows a polar view of daughter chromosomes, x 1,500. 
Fig. 31. Tragopogon pratensis. Late stage of anaphase, x 1,500. 
Fig. 32. Tragopogon pratensis. Telophase. A nuclear membrane has developed round the 
daughter chromosomes, x 1,500. 
