SEA-TEOETATTOS. 
33 
.•io singular a structure that we were for a long time doubt- 
ful whether it was a zoophyte or a kind of seaweed. The 
stem, ot a brownish colour and three inches long, has cir- 
cular leaves with lobes, and indented at the edges. The 
colour of these leaves is a pale green, and they are mem- 
branous and streaked like those of the ncliantums and 
Gingko biloba. Their surface is covered with stiff whitish 
hairs; before their opening they are concave, and enveloped 
one in the other. We observed no mark of spontaneous motion, 
no sign of irritability, not even on the application of galvanic 
electricity. The stem is not woody, hut almost of a horny 
substance, like the stem of the Gorgons. Azote and phos- 
phorus having been abundantly found in several crypto- 
gamous plants, an appeal to chemistry would be useless to 
determine whether this organized substance belonged to the 
animal or vegetable kingdom. Its great analogy to several 
sea-plants, with adiantum leaves, especially the genus eaul- 
erpa of M. Lauweureux, of which the Fueus proliter el 
Forskael is one of the numerous species, engaged us to rank 
it provisionally among the sea-wracks, and give it the name 
of i' ileus vitifolius. The bristles which cover this plant are 
found in several other fuci.* The leaf, examined with a 
microscope at the instant we drew it up from the water, did 
not present, it is true, those conglobate glands, or those 
opaque points, which the parts of fructification in the genera 
of ulva and fueus contain ; but how often do we find sea- 
weeds ill such a state that we cannot yet distinguish any 
trace of seeds in their transparent parenchyma. 
The vine-leaved fueus presents a physiological phenomenon 
of the greatest interest. Fixed to a piece of madrepore, this 
seaweed vegetates at the bottom of the ocean, at the depth 
of 192 feet, notwithstanding which we found its leaves as 
green as those of our grasses. According to the experiments 
of Bouguer, light is weakened after a passage of 180 feet in 
the ratio of 1 to 1477’8. The seaweed of Alegranza con io- 
quently presents a new example of plants which vegetate in 
great obscurity without becoming white. Several gerz s, 
enveloped in the bulbs of the lily tribes, the embryo of t e 
malvacete, of the rhamnoides, of the pistacea, the viscum, 
and the citrus, the branches of some subterraneous plants; 
* Fueus lycopodioldes, and F. hirsutus. 
VOL. I. 
D 
