190 Drew.—Reproduction and early Development of Laminaria. 
DESCRIPTION OF PLATES XIV AND XV. 
Illustrating Mr. Drew’s Paper on Laminaria. 
Fig. i. x 350. Section of reproductive areas showing gametangia embedded among paraphyses. 
Fig. 2 a, b , c. x 1,000. Gametangia separated by making scrapings of the reproductive areas. 
Stained with very dilute methylene blue. Stages in the development of the gametes are shown and 
the process^of aggregation of the oil globules. The cell-wall at the apex has commenced to degenerate 
and retains the blue stain. 
Fig. 3. x 1,000. A paraphysis separated by making scrapings of the reproductive areas. 
Stained with very dilute methylene blue. 
Fig. 4. x 1,000. A gametangium which has ruptured at the apex and is liberating the gametes 
and oil globules. 
Fig. 5. x 1,000. a. A gamete as liberated from the gametangia. b. A gamete which has lost 
its colouring matter and developed flagella, c and d. Stages in the fusion of the gametes, e. A zygo¬ 
spore resulting from the fusion of the gametes, f to /. Stages in the formation and growth of a cell 
of the sporophyte generation. 
Fig. 6. x 350. a and b. The sporophyte generation of Laminaria digitata , showing some 
cells in a state of division and the origin of the young plants of the gametophyte generation. 
c. A young Laminaria saccharina plant, the rhizoids still enclosed in the outer cell-wall. 
Fig. 7 - x 350. A young Laminaria digitata plant separated from the outer cell-wall, 
showing the lamina and rhizoids. 
Fig. 8. X 20. Young Laminaria digitata plant, showing the formation of the stipe. 
Fig. 9. x 20. Young L.aminaria saccharina plant, of the same age as that in Fig. 8. 
Fig. 10. x 20. Young Laminaria digitata plant, showing the formation of the disk at the 
base of the stipe. 
Fig. 11. x 20. Young Laminaria digitata plant, showing origin of the hapteres from the disk. 
Fig. 12. x 100. Longitudinal section of a very young Laminaria digitata plant. 
Fig. 13. X roo. Longitudinal section of a young Laminaria digitata plant through the 
stipe, showing the first stages in the formation of the disk. 
Fig. 14. x 50. Transverse section through the basal poition of a slightly older Laminaria 
digitata plant, showing the medullary tissue. 
Fig. 15. x 50. Longitudinal section through the stipe, disk, and one haptere of a Laminaria 
aigit at a plant. 
