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to be destitute of them. Air. Carroll found none of tbe larger Parmelise, but 
be states that Cetraria Islandica is found in great quantities on tbe deserts 
of tbe interior, and be thinks that a greater variety might be found if ex- 
amination were made of tbe flat- topped basalt mountains of tbe North- 
west. 
Distribution of the Diatomacece . — In a paper on tbe Protophyta of New 
Zealand Dr. Lauder Lindsay, after enumerating several new species of 
diatoms, and pointing out bow much remains to be done in tbe departments 
of Desmidiacese and Palmellacese, makes some interesting remarks on tbe 
cosmopolitan character of Diatomacese. He doubts whether any group of 
plants has a wider geographical range, or whether any will be found, when 
thoroughly known, to exhibit a greater number of cosmopolites, a larger 
proportion of species which are independent of the usual restrictions of 
climate or latitude, elevation or depth, aqueous or terrestrial growth — or a 
wider range in geological time. They are to be found in every part of the 
world hitherto explored by man, equally within the arctic circle as under 
the line : they occur at great elevations on the highest mountains of the 
world, as well as at great depths in the ocean ; in boiling or hot springs, and in 
the ashes ejected from active volcanoes; in running as well as stagnant, 
brackish or fresh as well as salt, water ; on the surface of soil of various 
kinds ; on dung and other decaying organic matters ; on lichens, algae, and 
other plants. They abound on the antarctic ice as far south as 78°, to 
such an extent as to give colour to the said ice and the associated water. 
Not infrequently they occur also in the dust of dust-winds, and they may 
therefore be looked for in that of those which sweep over New Zealand from 
Australia. Indeed, it is difficult to say where members of this cosmopolite 
family will not be discovered. 
Illustration of Natural Selection in Plants. — The recent continental discus- 
sions as to the origin of new animal races from monsters have led M. Naudin, 
the first of French botanists, to call the attention of the scientific world to some 
remarkable instances of the origination of species and races by variation. 
He states numerous examples, but we shall quote only the following. In 
1861 M. Godron found in a batch of seedlings of Datura tatula (a plant 
whose fruit is covered with spines) a single specimen whose fruit was per- 
fectly smooth. The seeds taken from this plant produced in 1862 a number 
of plants all of which resembled the parent. Their seeds gave rise to a 
third generation similar to the second, and M. Naudin has seen the fourth 
and fifth generation in his own museum. In all he says there are a hundred 
individuals not one of which shows the slighest tendency to return to the 
character of the typical species. They in fact constitute an entirely new 
race. By crossing them with the original stock, M. Godron has obtained 
forms which are identical with I), stramonium and D. Icevis, which have 
hitherto been regarded as decidedly distinct species. If we add his 
peculiar variety of D. tatula and call it D. inermis we shall have four species 
produced by variation. M. Naudin thinks that the variations which give rise 
to new species do not require the immense number of years for their produc- 
tion, which is usually assigned to them, but that they occur brusquely , and 
thus, the sought for connecting links have really no existence. 
Spontaneous Movement of Colocasia esculenta. M. Lecoq describes the 
