
234 PROFESSOR ALEXANDER DICKSON ON THE EMBRYOGENY OF 
Figure 2. Section of very young fruit-lobe. The germ is now pyriform, with pointed base fitting into 
the apex or micropylar extremity of the embryo-sac. > he 
Figure 3. Embryo-sac and contents from preceding section, highly magnified. The cellular structure 
of the pyriform germ is seen. In the protoplasmic lining of the inner surface of the 
embryo-sac nucleated particles are embedded in a single layer, representing a transitory 
endosperm. The protoplasm has shrunk in the preparation, as represented in the figure; 
but I am not certain whether its well-defined outer boundary is the wall of the embryo- 
sac itself or merely the so-called “primordial utricle” of the sac. 
Figure 4. Section of young fruit-lobe, further advanced. The germ is now flask-shaped (like a soda- 
water bottle), and has become somewhat elongated. Enlarged figure of this germ in 
Plate XV. fig. 13. 
Figure 5. Section of young fruit-lobe, still further advanced. The campylotropal curvature of the 
micropylar extremity of the young seed is now much more pronounced. The flask- 
shaped germ is now more elongated, and exhibits a knee-like bend about its middle, 
Enlarged outline figure of this germ in Plate XV. fig. 14. 
Figure 6. Section of young fruit-lobe, still further advanced. The pointed base of the germ is now 
much elongated. A slight bulging on the outer aspect of the body of the germ at the 
knee-like bend indicates the commencement of the extra-seminal root-process. The 
embryo (“embryonal globule”) and suspensor are distinctly differentiated. 
Figure 7. Section of young fruit-lobe, still further advanced. The extra-seminal process now appears 
as a short thick cylindrical structure which has bored through the seed-coat, and has 
forthwith begun to insinuate itself into the substance of the carpel. Enlarged figure of 
this germ in Plate XV. fig. 17. 
Figure 8. The same, further advanced. The extra-seminal process has now run some little distance in 
the substance of the carpel. 
Figure 9. The same, still further advanced. The extra-seminal process has now run for a considerable 
distance in the substance of the carpel, keeping just outside the inner surface of the 
cavity of the seed-vessel. The two cotyledons of the embryo have now distinctly 
appeared, 
Figure 10. Abnormality. Section of young fruit-lobe apparently somewhat younger than the preced__ 
ing. The “extra-seminal” root-process is intra-seminal, and the suspensor and embryo 
are shrunken and misthriven. 
PuaTe XV. 
Tropeolum speciosum. 
Figure 11. Pyriform germ, with cellular structure indicated, the same as represented in Plate XIV, 
figs. 2 and 3. 
Figure 12. Young germ, now shortly flask-shaped. Cellular structure indicated. Stage intermediate 
between that represented in Plate XIV. fig. 2, and that in fig. 4. 
Figure 13. Flask-shaped germ, somewhat elongated, the same as represented in Plate XIV. fig. 4, 
Cellular structure indicated. Enlargement of the cells of the base (b) and of the neck of 
the flask (the future suspensor, susp), now commencing. 
Figure 14. Outline figure of germ represented in Plate XIV. fig. 5. The embryo, suspensor, and (more 
faintly) the extra-seminal process, are now becoming differentiated. Body of germ with 
knee-like bend. 
Figure 15. Germ somewhat further advanced. Cellular structure indicated. 
Figure 16, Outline figure of germ at a stage a little further advanced than that in Plate XIV. fig. 6. 
The “embryonal globule” well marked, and the extra-seminal process visible as a very 
distinct rounded projection (esr). 
Figure 17. Germ from section represented in Plate XIV. fig. 7. Cellular structure indicated. 

