& 
Notice of Harvey's Marine Alg@ of North America, 3 
*“ The sea, too, teems with animal life,—that ‘* great and wide se 
wherein are things creeping pe asa ‘bape small Ang great beats, 
affords scope to hordes of animals, from the * Leviat whale 
microscopic polype, transparent’as the ae in which . i os aad 
only seen by the light of the phosphoric g gleam which he emits. Now 
this exuberant animal creation could not be maintained without a veg- 
etable substructure. It is one of the laws of nature that animals shall 
feed on organized matter, and vegetables on unorganized. For the 
support of animal life, therefore, we require vegetables to change the 
mineral constituents of the surrounding media into suitable nutriment. 
**In the sea this office of vegetation is almost exclusively committed 
to the Alge, mend we may judge of the completeness with which they 
execute their mission by the fecundity of the animal world which de- 
prods upop thers Not shee I would assert that all, or nearly all, tee 
and there are myriads of the lower in organization which do depend 
Bpon them Pane: 
the higher orders of Alge feeders I may mention the 
Turtles, whose green Jat, so prized by ‘aldermanic palate, put peels 
be colored by the unctuous green juices of the Caulerpe which 
they browse. But without further notice of those that directly rbepend 
on the Algz, it is manifest that all must peered though indirectly, 
__ depend on whatever agency in the first instance seizes on inorganic 
: Matter, and converts it into living substance siiiable to enter into the 
composition of animal nerve and muscle. And this agency is assuredly 
the office of the vegetable kingdom, here confined in the main to Algz ; 
we thus sufficiently establish our polos) that the =Alens are ,indispensa- 
ble to the continuance of organic life i in the sea. 
“As being the first vegetables that at ney apo dead tated and as 
affording directly or indirectly a past waler: cde Alge 
are entitled to notice. Yet this is ox one half of the task committed 
to them. © Equally important is the influence which their growth exerts 
: _ on the water and on the air. The well known fact that plants, whilst 
Joos fix carbon in an organized form in extending their bodies re! the 
- growth of cells, exhale oxygen gas in a free state, is true of t 
as of other vegetables. By this action they tend to keep pai e 
water in which they vegetate, and yield also a considerable portion of 
; eee gas ta. ) the be sone Thave already stated | that whenever 
wherever an extensi ve surface o of shallow 
s exposed to ie oe Co ¢7 
and this Vegetation usually continues 
another as it dies out, as long as the p 
drying up of the land, the Conf 
arcely more than mem 
ae 
