Development of Laminaria bulhosa , L amour. 49 
attachment corresponds fairly well with the irregularity of 
outline of the disc-end of the haptere. The primary organ of 
fixation,/, has fused with hapteres of the first row. It has 
not yet been torn away from its attachment by the formation 
of the wide base of the bulb. It will be seen at a glance how 
great an increase in stability is attained by such an extension 
of fixing base. Only some of the second row have reached 
the substratum, while those of the third row are still com- 
paratively small. 
Fig. 8 shows a double twist at the base of the stalk : the 
flat portion above the twist shows a perfectly straight outline. 
The lamina is splitting up into its numerous segments, and 
the bulb has assumed an irregular form. Finally, Fig. 9 re- 
presents a specimen which is a good deal older than any yet 
figured. The great hollow bulb has been formed, and has 
assumed the dark opaque colour of the adult. The numerous 
tubercles may or may not represent series of rudimentary 
hapteres, although, under normal conditions, it is improbable 
that any of them would develope into attaching organs. The 
further development includes further changes. The bulb may 
reach a much greater size. The specimen figured by Stack- 
house 1 , at natural size, measures ioJ inches across ; and it is 
stated that a specimen has been collected which measured a 
foot in diameter. In spite of this great increase in size, the 
bulb remains hollow, and its walls do not increase in thickness 
to any appreciable degree. 
Fig. 10 represents a portion of an old bulb on which spor- 
angia are plentifully developed. These are present on all 
parts of the outside of the bulb, as well on the surface of the 
bulb itself as on the tubercles developed upon it ; and the 
sporangia cover these tubercles to their tips. They are not, 
however, confined to the external surface, but are also plenti- 
fully developed on the inner surface of the hollow bulb. 
The stalk soon becomes differentiated into two parts by 
the development of the ridge. The lower part remains 
1 Nereis Britannica, 1801. 
E 
