766 
Pearson.—On the Embryo of Welwitschia. 
EXPLANATION OF PLATE LXIV. 
Illustrating Prof. Pearson’s paper on the Embryo of Welwitschia. 
All the figures are prepared from longitudinal and approximately median sections. 
Figs. 4 and 5 are microphotographs. 
Figs. 1-3, 6 and 7 are drawn under Zeiss D, ocular 2, with the aid of the camera lucida. x 305. 
Fig. 1. A stage somewhat more advanced than that of Text-fig. 1. x — cells of 1 lower ring ’ ; 
c = apical initial cells. 
Fig. 2. A slightly more advanced stage, x — additions to the suspensor derived from the cells 
of the ‘ lower ring ’ ; y — the cells which will form the next additions to the suspensor; c = apical 
initial cells. 
Fig. 3. A more advanced stage, a, b, d — suspensor cells ; end. — endosperm cells. 
Fig. 4. A more advanced stage in which the suspensor (S) has completed its growth in thick¬ 
ness. St. — stem dome ; R = root meristem. This precedes the stage shown in Text-fig. 2. 
Fig. 5. Embryo of mature seed, c = cotyledons ; l.c. — lateral cones ; other lettering as in 
Fig. 4. 
Fig. 6. Twin-embryos resulting from bifurcation. 
Fig. 7. A young embryo formed as a lateral branch from an older one. One of the initial cells 
of the latter is in course of division. 
