5 1 
On Pallavicinia decipiens , Mitten . 
modification from normal division to a possibly reduced, and 
at any rate much compressed, type of karyokinesis is 
traceable within the genera comprised in the Hepaticae. 
There are, furthermore points of theoretical interest con- 
nected with the modifications just described, but it is best to 
postpone the discussion of these questions until further 
investigations have rendered it possible to review and com- 
pare the process in a wider range of species than can be done 
at the present time. 
EXPLANATION OF FIGURES IN PLATES 
VI AND VII. 
Illustrating Mr. Farmer’s paper on Pallavicinia decipiens , Mitten. 
Figs. 1-37 refer to Pallavicinia decipiens ; Figs. 38 and 39 to Aneura multifida. 
Fig. 1. Barren plant (natural size). 
Fig. 2. Fertile frond (enlarged), a , involucre, surrounding a group of arche- 
gonia : b , colesula, from which a sporogonium is issuing. 
Fig. 3. Longitudinal section of apex of rhizome, in horizontal plane, with apical 
cell : c, the apical cell of lateral branch. 
Fig. 4. Longitudinal section of rhizome-branch which is growing up to form 
a frond. 
Fig. 5. Longitudinal section of rhizome, somewhat oblique, with an apparently 
triangular apical cell': c, apical cell of branch. 
Fig. 6. Young branch of rhizome. 
Fig. 7. An older ditto, showing the central strand. 
Fig. 8. Transverse section of rhizome. 
Fig. 9. Transverse section of apex of rhizome : a, apical cell : c, apical cell of 
branch (cut below the surface). 
Figs. 10, 10 a. Young apices of lateral branches forming their apical cells. 
Figs. 11, 12, 13. Adventitious buds, from ventral surface of frond beneath 
archegonial groups. 
Fig. 14. Apex of a branch of the frond. 
Fig. 15. Group of archegonia, one has been fertilized and contains a three-celled 
embryo : i, involucre : p , colesula. 
Figs. 16, 17. Young embryos. 
Fig. 18. Longitudinal section of antheridial branch (somewhat diagrammatic). 
Fig. 19. Spore-mother-cell, with ingrowing cell- walls. 
Figs. 20-29. Stages in development of spores. 
E 2 
