Scientific. Reviews. BO] ’ 
Ynity of the port of Alexandria and the coasts of Syria to those of Suez and the 
Red Sea, the marine plants of the former, in regard to species, differ almost en- 
tirely from those of the latter. Bory de St. Vincent characterizes each of his 
Mediterranean Seas by a vegetation different from that of the Arctic, Ailantic, 
Antarctic, Indian, and Pacific Oceans, and, to a certain extent, he is probably 
correct, as such seas are of less depth, often of a higher temperature, and more 
directly influenced by the countries which more or less enclose them. ‘The seas 
which he considers as Mediterranean, are the Mediterranean properly so called, 
the Baltic Sea, the Red Sea, the Persian Gulf, the Chinese Sea, the Seas a 
Okhotsk and Bhering, and the West Indian Sea, tone with the Gulf of Mexi- 
co, denominated by him The Columbian Mediterranean. 
“‘ Every great zone presents a peculiar system of existence: and it is said, that 
after a space of twenty-four degrees of latitude, a nearly total change is observed 
in the species of organized beings, and that this change is mainly owing to the 
influence of temperature. Lamouroux remarks, that if this holds good, as we 
know it to do, to a wonderful extent in phenogamous plants, it should also ex- 
ert some corresponding force upon marine vegetation. -It is unquestionable that 
the A/ge are found on our own coasts, in the greatest abundance, during the 
summer months, and in unusual luxuriance in hot seasons. It is probable also, 
observes the same author, that these plants may be acted on by the temperature 
of the water at greater or less depths; and that the species which grow at the 
bottom of the ocean may have some resemblance to those of the Polar Circle. 
On the shores of the British Islands it is easy to perceive that some species, 
Gelidium corneum, Phylophora rubens, and Spherococcus. coronopifolius, for 
.example, become more plentiful and more luxuriant as we travel from north to 
south ; and, on the other hand, that Ptilota plumosa, Rhodomela lycopodioides, 
Rhodomenia sobolifera, and several others, occur, more frequently, and in a finer 
state, as we approach the north. Odonthalia dentata, and Khodomenia cristaia, 
are confined to the northern parts of Great Britain, while the Cystoseire, Fucus 
tuberculatus, Haliseris polypodioides, Rhodomenia jubata, R. Teedii, Micro- 
cladia glandulosa, Rhodomela pinasiroides, Laurencia tenuissima, Iridea re- 
niformis, and many others, are confined to the southern parts. Others again, 
such as the Fwci in general, the LAMINARIEZ, many Delesserie@, some Nito- 
phylle, Laurentie, Gastridia and Chondri, possess too extended a range to be 
influenced by any change of temperature between the northern boundary of Scot- 
land and the south-western point of England. The researches and calculations 
of Lamouroux have demonstrated satisfactorily, that the great groups of Alge 
do affect particular temperatures or zones of latitude, though some genera may be 
termed cosmopolite. Setting aside the great division of articulated Alge, of 
which we know but little, the SrPHONE, or at least the genus Codiwm, and 
the ULvaceg, are scattered over every part of the world. Codiwm tomentosum 
is found in the Atlantic, from the shores of England and Scotland to the Cape of 
Good Hope; in the Pacific from Nootka Sound to the southern coast of New 
Holland. It abounds in the Mediterranean, on the shores of France, Spain, and 
Africa, and is common in the Adriatic. More recently it has been also brought 
from the coasts of Chile and Peru. This plant, however, is not a social one— 
to make use of a term that Humboldt has applied to some phenogamous plants. 
it grows even in the same locality, in a solitary and scattered manner. The 
ULVAcE#, on the contrary, are strictly social, and preserve this character in 
every part of the world. They appear, however, to attain the greatest perfection 
in the polar and temperate zones, although I have very fine Porphyre from the 
Cape of Good Hope. That they are capable of sustaining very extreme cold, is 
proved by the fact, that fine specimens of Enteromorpha compressa were picked 
up in high latitudes of the Arctic Ocean, by some of the gentlemen who accom- 
panied Captain Sir Edward Parry in his second Voyage of Discovery. ‘The 
DicTYOTEA, of which we have eight representatives in Scotland, and thirteen 
in England, increase both in quantity and number of species, as we approach 
the Equator. The FucoipDE#, in a general sense, increase as we leave the 
