922: NOTICES OF BOOKS. 
trations the former part, which consisted of the more dingy-coloured 
species. Every frequenter of our coast has been more or less struck 
by the beauty and elegance of these productions, which are in conse- 
quenee favourite objects of collections, and the interest is much in- 
creased when the structure is observed even under low magnifying 
| powers. i 
The RHODOSPERMEÆ are not however wholly confined to salt water. 
The genus Bostrychia not only occurs in brackish water, but some grow 
even in perfectly fresh water, in mountain streams far removed from the 
sea. The same species, as in the case of B. vaga of Kerguelen's Land, 
may occasionally be traced from the rocks and stones about high-water 
mark to a considerable distance inland. Six species of this division, 
belonging to the genera Bostrychia, Gymnogongrus, and Ballia, have 
been found by M. Leprieur in Cayenne at a height of from 100 to 150 
métres above the level of the sea; and though occurring at a distance 
from the shore, they have precisely the same smell, and probably the 
same chemical properties, as their salt-water congeners. 
As regards the exeeution of the work, which we hope will be widely 
diffused in this country, we may remark that the figures, all of which 
are coloured, are just in the style of those of the * Phycologia Britan- 
nica,’ and give all that can be attained at so moderate a price; and not- 
withstanding a larger outlay, though neither necessary nor practicable, 
might have secured in some instances a greater degree of neatness and. 
precision in the colouring, nothing is wanting to the general effect of 
the illustrations; and the dissections are well made out, and available 
at once for the purposes of science. 
The importance of this work is by no means confined to any general ; 
physiological interest which may be attached to the subject, much less 
to any restricted local or national claims, but the student in all parts of 
the world, and more especially in our own latitudes, will find it quite 
indispensable to the satisfactory advance of his knowledge. For m 
only are the geographic details most important and often most precise, 
but there is so much similarity between the American and European 
species, or between certain groups and those of other countries, that 
henceforth no student who makes any pretensions to due research can 
safely profess his ignorance of these volumes. We know indeed that 
both in this and other countries works have appeared betraying the 
most complete ignorance of contemporary labours; but the inevitable 
