Life-history of No to thy las. 
401 
EXPLANATION OF FIGURES IN PLATES 
XX AND XXL 
Illustrating Mr. Mottier’s paper on Notothylas. 
Fig. 1. The three successive longitudinal sections of an eight-celled embryo of 
Notothylas orbicularis ; the arrow pointing toward the fore edge of the thallus. 
X520. 
Fig. 2. Longitudinal section of an older embryo. X520. 
Fig. 3. Longitudinal section of a young sporogonium of Notothylas , showing 
columella and four archesporial cells arching over it ; I- 1 , basal wall, x 372. 
Fig. 4. Longitudinal section of an older sporogonium of Notothylas ; the cells 
of the archesporium with contents indicated. Those just over the apex of columella 
have divided by tangential walls. X372. 
Fig. 5. Similar to Fig. 4, but a little older, x 372. 
Fig. 6. Transverse sections of sporogonium of about the same age as 5 \ a taken 
at a-a (5) ; b at b-b , archesporium indicated ; c at c-c. x 372. 
Figs. 7-14. All the successive cross-sections of a sporogonium of Notothylas 
a little younger than Fig. 5, from the basal wall upwards, x 372. 
Fig. 15. Transverse section of a young sporogonium of Anthoceros, showing the 
four central cells, the columella surrounded by the archesporium, and then the 
peripheral row. x 372. 
Fig. 16. Longitudinal section of an eight-celled embryo of Notothylas with the 
surrounding cells of the thallus. X372. 
Fig. 17. Longitudinal section, showing half of the lower part of a nearly 
mature capsule of Notothylas , in which the origin of the sterile cells from the 
archesporium is evident. At the boundary between foot and capsule the cells are 
becoming slightly elongated preparatory to the separation of the capsule, x 250. 
Fig. 18. Longitudinal section of a small sporogonium of Notothylas with a 
portion of the foot omitted. Several spore-mother-cells lying loosely in the spore- 
chamber are rounded off and almost ready to divide. The columella is small, but 
unquestionably present ; the archesporium extends to the region of the basal wall, 
x 250. 
Fig. 19. Longitudinal section of sporogonium of Notothylas , showing foot and 
lower portion of capsule. The cells of the foot are quite regular ; the columella 
and archesporium extend entirely to the foot, x 350. 
Fig. 20. Longitudinal section of an apparently starved embryo of Notothylas , 
from a very slender lobe of the thallus. x 372. 
Fig. 2i. Portion of a columella to which adhere several sterile cells and three 
spore-tetrads. Fresh preparation in dilute glycerine. X94. 
Fig. 22. Longitudinal section of an archegonium of Notothylas shortly before 
opening. The contents of the cells immediately surrounding the archegonium are 
indicated, x 750. 
