198 Farmer and Digby. — Studies in Apospory and 
PLATE XVII. 
Fig. 14. Prothallial cell with nucleus in equatorial plate stage, x 1500. 
Fig. 15. Nucleus of the antheridial cell in equatorial plate stage; the daughter-cells will give 
rise to the spermatocytes, x 1500. 
Fig. 16. Spermatocyte with antherozoid differentiating, x 1500. 
Fig. 17. ‘ Bulbous’ prothallium on frond. Three reduced prothallia are also shown. From 
a cleared preparation. f surface of leaf; Ar, archegonium; s, abortive sporangium with prothallial 
outgrowth. 
Fig. 18. ‘Bulbous’ prothallium bearing embryo, from a preparation mounted entire, f the 
surface of the leaf. 
Fig. 19. ‘ Bulbous ’ pro thallium with earliest rudiment of sporophytic tissue (sf) (longitudinal 
section). 
Fig. 20. ‘ Bulbous ’ prothallium (section) with young embryo. 
Fig. 21. a, b, c, d , four serial sections through a bulbous prothallium bearing an embryo. 
Fig. 22. Section through older embryo. R , the root. 
Figs. 23, 24. Nuclear division in the cells of young embryo. 
Athyrium Filix-foemina var. clarissima, Bolton, x 1500. 
Fig. 25. Nucleus of prothallial cell, x 1500. 
Fig. 26. Nucleus of prothallial cell in mitosis, x 1500. 
Fig. 27. Nuclear division in embryo, x 1500. 
PLATE XVIII. 
Fig. 28. Oosphere (contracted) in the venter of the archegonium. n , neck of archegonium; 
a, antherozoids. 
Fig. 29. Embryo (parthenapogamous) within the venter of archegonium. n , neck of arche- 
gonium. a, antherozoid ; the arrow -> shows the direction of the apex of the prothallium. In the 
epibasal half two nuclei are shown separated by the (invisible) median wall. In the hypobasal half 
two nuclei are shown separated by a wall parallel with the basal wall BB. 
Fig. 30. Transverse section of the epibasal half of a young embryo showing the median and 
transversal walls. The section was taken transversely through the prothallium at right angles to its 
axis of growth. 
Athyrium Filix-foemina var. unco -glo meratu m , Stansfield. 
Fig. 31. Nucleus from prothallial cell, nu, nucleoli, x 1500. 
Athyrium Filix-foemina. 
Fig. 32. Spore-mother-cells with the heterotype chromosomes, x 2250. 
Fig. 33. Prothallial cell with nucleus, x 1500. 
Fig. 34, a, b, c. Spermatocytes with stages in the differentiation of antherozoid. x 1 500. 
Lastrea Filix-mas. 
Fig* 35* Oosphere in archegonium showing fertilization stage, a. the antherozoid in the 
oosphere ; a 1, antherozoids that have failed to penetrate the oosphere ; B , the ‘ body ’ in the oosphere. 
The track of the antherozoid in the oosphere is seen to pass across it. JV, neck of archegonium. 
Scolopendrium vulgare var. crispum Drummondae . 
Fig. 36. Oosphere within the venter of the archegonium. The nucleus shows tendency td 
amitosis. v, the nucleus of ventral canal-cell. 
Fig. 37* Young embryo in section, ar, part of the archegonium neck. 
Lastrea pseudo-mas var. polydactyla, Wills. 
Fig. 38. Nuclear division of young archesporial tissue, x 1500. 
Figs. 39, 40. Heterotype mitosis in spore-mother-cell, x 1500. 
Fig. 41. Nucleus in mitosis from prothallium, x 1500. 
