LINDSAY, ON THE PROTOPHYTA OF NEW ZEALAND. 107 
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 lati- 
tude, 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, alge, 
and other plants. They abound on the Antarctic ice as far 
south as 78°S. 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. 
Practically, Diatoms may be divided into two great 
groups :—1. the terrestrial, including fresh-water forms ; and 
2. the marine. 
Exclusively to the former category belong those which I 
collected in Otago, and which are enumerated in the list 
hereinbefore given. Members of this group are to be looked 
for in the mud and scum of ponds, lakes, ditches, lagoons, or 
marshes—especially where the water is stagnant and over- 
grown with chlorospermous or confervaceous alge: or on the 
surface of rocks or soil over which water constantly trickles, 
in damp, shady situations—for instance, in ravines by the 
sides of waterfalls, in the dense moist bush. Their collection 
is easy ; and their siliceous coats render their beautiful struc- 
ture and characters readily preservable. The scum or the 
surface of the sand, rock, soil, or water above referred to, has 
merely to be scraped with a metallic or other spoon, and the 
collect, after filtration from superfluous water, whether mud, 
marl, disintegrated rock, conferyaceous vegetation or mixture 
of mosses, hepatice and soil, placed in small phials and 
securely corked. In this way my own small collections in 
Otago were hurriedly made. In this way collections have 
been made in all parts of the world and forwarded to the late 
Dr. Greville, so long our first authority in this beautiful but 
intricate department of botanical research—who, by this 
means, was enabled to contribute, in great measure through 
the pages of this Journal, many valuable and original additions 
to our knowledge of the Diatomacez. 
