524 Harper . — Cell- Division in Sporangia and A sci. 
EXPLANATION OF FIGURES IN PLATES 
* XXIV— XXVI. 
Illustrating Professor Harper’s paper on Cell- Division in Sporangia and Asci. 
All figures were drawn with the aid of the Abbe camera lucida, and with the 
Zeiss apochromatic objectives 8 mm., or 2 mm., Num. Ap. 1. 40. 
PLATE XXIV. 
Figs. 1-8. Synchitrium decipiens. 
Fig. 1. Uninucleate cell almost full grown, x 250. 
Fig. 2. Multinucleate stage showing progressive cleavage by furrows from the 
surface. Central mass of protoplasm not yet segmented, x 500. 
Fig. 3. Portion of cell showing two nuclei and two cleavage- furrows, x 1500. 
Fig. 4. Median section of cell showing cleavage farther advanced, x 250. 
Fig. 5. Section from surface of a cell in early stage of cleavage, x 500. 
Fig. 6. Cell after segmentation is completed, showing uninucleate proto- 
spores. x 250. 
Fig. 7. Section of sporangium with spores after they have become polygonal by 
mutual pressure and contain several nuclei, x 500. 
Fig. 8. Mature spores, multinucleated and with cell-walls, x 500. 
Figs. 9-33. Pilobolus crystal/inus, except figs. 28-32. 
Fig. 9. Median longit. section of tip of sporangiophore bearing young sporangium . 
Figs. 9-12 show the nuclei merely as dots. 
Fig. 10. Tip of slightly older sporangiophore with sporangium; section a little 
to one side of the middle. 
Fig. 11. Median section of older sporangium, showing course of the protoplasmic 
flow from the mouth of the sporangiophore. a, section of protoplasmic ridge 
around the mouth of the sporangiophore. 
Fig. 1 2. Median section of sporangium at stage when columella is forming, show- 
ing cleavage-furrows at base and flattened vacuoles above. 
Fig. 13. Section of spore-plasma and sporangial wall just before cleavage begins, 
x 1250. 
Fig. 14. Section of spore-plasma from base of sporangium, showing first appear- 
ance of superficial cleavage-furrows, a, collar ; b, columella-cleft ; c, section of 
protoplasmic lining of columella ; d , angular vacuole in spore-plasma, x 750. 
Fig. 15. Same as Fig. 14, but cleavage further advanced; a , sporangial wall, x 750. 
PLATE XXV. 
Fig. 16. Section through a portion of the upper part of a sporangium, showing 
irregular sausage- shaped bodies formed by cleavage of the spore-plasma ; a little 
older than Fig. 15. x 75 °* 
Fig. 17. Similar section to Fig. 16, but older, showing uninucleate protospores 
formed by cleavage, x 750. 
Fig. 18. Protospores with dividing nuclei, young daughter nuclei connected by 
remains of spindle fibres, a, collar; b , protoplasm of columella, x 75°* 
