692 THE AMERICAN NATURALIST. [VoL. XXXV. 
Notes on the Botanical Investigation of the Fzróes," and C. H. 
Ostenfeld's * Notes on Geography, Climate, Topography, Geology, 
and Industrial Conditions." Mr. Ostenfeld's notes are furnished 
with excellent illustrations, so that we reach Mr. Bérgesen’s list 
of the alga with a good understanding of the conditions that 
have made the flora what it is. This flora must have been intro- 
duced since the last glacial epoch, and, according to the writer, it 
is probably more than anything else the birds that have gradually 
contributed the various fresh-water algae found on these eighteen 
rocky islands, only five of which have an area of over roo kilo- 
meters each. In their migrations through Great Britain to the 
Arctic region the birds make a stop on these islands, the distance 
from the northernmost British isles being only a two hours' flight. 
So we find two elements in the Ferée flora, a southern, agreeing 
with that of Great Britain, and including some forms supposed to 
be peculiar to the latter, and an Arctic element; the one brought by 
the spring migration, the other by the return in autumn. 
forms. The desmids, with 175 species, constitute more than half 
of the whole, — the other -green algze number 103 ; there are forty- 
one Cyanophycez ; one Nitella, one brown alga, Hydrurus fetidus, 
and one red alga, Chantransia hermanni, complete the list. 
Two species. of Enteromorpha, Æ. compressa and Æ. anicrococca 
Jorma subsalsa, were found in brooks at a height of 200-300 meters. 
The former has been considered exclusively marine, the latter has 
been found in.brackish pools in the Arctic regions ; their occur- 
rence in running fresh water is quite noteworthy. Beside several 
new varieties and forms, two new species are described, Zuastrum 
lyngbyei and Cladophora lyngbyei; a plate of the latter, however, 
shows a form of branching which hardly accords with Cladophora; 
it would seem as if the plant belonged rather in Siphonocladus. 
There are four good plates and an excellent map, and the whole 
is in unexceptionable English. 
(Hirn, Karl E. « ‘Monographie und Iconographie der Oedogonia-. 
cien," Acta Societatis Scientiarum Fennice. Helsingfors, 1900.) This 
volume of 400 quarto pages and sixty-four plates is a notable addition 
to the working tools of the systematic algologist. One hundred 
and ninety-nine species of CEdogonium, forty-four of Bulbochete, 
and one of (Edocladium are composed in the family. Full diag- 
noses of all the species, with their many varieties and forms, M 
