June, 1905.] Embryo Sac and Embryo of Batrachium. 
359 
DESCRIPTION OF PLATES. 
For the drawings a Bausch and Lomb camera lucida and 
microscope were used with oculars 2, 1 and Y 2 objectives 
2-3, 1-6 and 1-12; Figs. 1, 8-11, 16-24, 26, 28, 30, 34, 36, 38 and 
39 were drawn under the 1-inch ocular and the 1-6 objective; 
Figs. 2, 3 and 37 with the 2-inch ocular and the 1-6 objective; 
Figs. 4, 5 and 25 with the 34‘inch ocular and the 2-3 objective; 
Figs. 6, 7 and 14 with the ocular and the 1-6 objective; 
Fig. 12 with the ]/<-inch ocular and the 1-12 objective; Fig. 13 
with the 1-inch ocular and the 1-12 objective; Figs. 29 and 33 
with the 2-inch ocular and the 2-3 objective. 
Fig. 1 — Section of the receptacle showing two stages in the development 
of the carpels. 
Fig. 2 — Section of young carpel showing the lamina. 
Fig. 3 — Section of carpel showing tip of carpellary leaf folded to enclose 
the nucellus. 
Fig. 4 — Section of carpel showing cavity closed and integument well 
developed. Megasporocyte divided. 
Fig. 5 — Longitudinal section of carpel showing elongating style and 
stigma and the micropyle. 
Fig. 6 — Section of young androecium showing division of archesporium 
into wall cells and sporogenous cells. 
Fig. 7 — Wall cells divided to form parietal tapetum. Outer wall cells 
beginning to divide. 
Fig. 8 — Delayed division in one primary wall cell. Sporogenous cell 
dividing to form axial tapetum. 
Fig. 9 — Central section showing tapetum fully developed and a splitting 
between the peripheral tapetum and the sporogenous tissue. 
Fig. 10 — Section near tip of stamen showing binucleate tapetum and 
spindle. 
Fig. 11 — Longitridinal section of more mature stamen showing the same- 
Fig. 12 — Microsporocyte dividing. 
Fig. 13 — Tetrads. 
Fig. 14 — Disintegrating microspore and two celled pollen grain. 
Fig. 15 — Mature pollen grains showing tube and two sperm nuclei. 
Fig. If) — Nucellus and archesporial cell. 
Fig. 17 — Double archesporium. 
Fig. 18 — Megaspores. 
Fig. 19 — Nucellus showing megaspores and division in epidermal layer. 
Fig. 20 — Two-celled embryo sac. 
Fig. 21 — Four celled embryo sac. 
Fig. 22 — Eight celled embryo sac. 
Fig. 23 — Eight celled embryo sac showing synergidae and oosphere, con- 
jugating polar nuclei and antipodals. 
Fgi. 24 — Seven celled embryo sac showing egg apparatus, definitive 
nucleus and antipodals. Embryo sac enlarging in antipodal 
region. 
