Linnazan Society. 263 



place, for by a gradual arching or receding upwards of that part of 

 the germ which closes the cavity of the sporule the germ becomes 

 hollow, the hollow communicating with the cavity of the sporule, 

 which is of course proportionably enlarged. The germ now gra- 

 dually points in two places, which are by no means fixed, but occur 

 in various situations according to the position of the sporule in rela- 

 tion to the light. The direction of the first leaf is generally in the 

 direction of the axis of the sporule, or rather a little inclined, and 

 that of the first root at right angles or lateral, but very soon chan- 

 ging to an opposite direction to that of the leaf. This would be the 

 constant direction if the sporules were always left to themselves free 

 from entanglements, on account of the peculiar structure of their 

 outer coats ; the spongy fibro- cellular texture of the superior third 

 of which, causing that end to be the most buoyant in the water, ex- 

 poses the superior surface of the germ to the direct action of the 

 light ; but as it cannot always happen that the sporules should be 

 free, the direction of the leaf and root is sometimes quite the reverse, 

 and at others both leaf and root are lateral, but proceeding from 

 opposite sides of the germ. These two points gradually lengthen, 

 and if dissected each will be found to consist of a closed sheath, con- 

 taining in one instance the leaf, in the other the root in the form of 

 a conical process like a finger in a glove. The young leaf, which is 

 taper and its cells crowded with green granules, being in advance of 

 the root, which is obtuse and destitute of green granules, bursts 

 through the summit of its sheath when it has become rather longer 

 than the sporule, whilst the root, although more backward in its de- 

 velopment, pierces its sheath before it is as long as the sporule. The 

 sheaths are not distinct, but communicate with each other ; and the 

 only point of connexion between the sheath (there being in fact but 

 one) and the germ is around its base close to the sporule, so that 

 nearly the whole of the germ is inclosed in this sheath. Besides 

 this sheath which embraces the upper part of the root, there is an 

 exceedingly delicate expansion, which so closely embraces the ex- 

 tremity of the root like a cap, that it is only by a careful examina- 

 tion that it can be discovered. I am not aware that this has ever had 

 any connexion with the sheath through which the root bursts, but, 

 on the contrary, I believe it to be a distinct formation. After the 

 leaf has grown many times the length of the sporule, or about 2 

 lines long, another leaf grows from the germ close to the first, to 

 which it is in all respects similar, and then a bud begins to be de- 

 veloped from some indefinite part of the germ, but like the leaves 

 and root from within the sheath, which is now frequently much lace- 



