AND PRESERVING PLANTS. 
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labelled with locality, approximate height above sea -level, date, and 
character of the water, whether fresh, brackish, cold, or thermal. 
Water- weeds, Sphagna, etc., growing in lakes and pools, should be 
gathered, washed, and gently squeezed in water, and the sediment 
treated like the muds. Floating patches of scum which have risen 
to the surface, buoyed by bubbles of gas on a warm sunny day, 
should be secured with the net. These are often rich in Diatoms. 
It must be remembered that small quantities are very difficult to 
manipulate afterwards. 
Marine Diatoms from the surface should be collected by tow-net as 
described above under " Phyto-plankton." 
Ripple-markings on warm, sunny days often exhibit a yellow- 
brown colour on the sides opposite the sun. This sand should be 
scraped, and treated in a pan as recommended for the muds. The 
process should be often repeated because the proportion of Diatoms 
to sancl-grains is often small. Rock-pools between tide-marks 
should be examined, and sloping or horizontal rock surfaces scraped. 
Algse in such pools and beyond low-water mark should be treated as 
noted under "Fresh-water Weeds." Shells, especially living ones, 
covered with Zoophytes and small Algaa should be scraped, and the 
scrapings sent as they are. The contents of the stomachs of 
Holothurians, Ascidians, herbivorous Molluscs, are often very rich in 
Diatoms. Dredgings and rubbish from trawling-boats are often 
fruitful in diatomaceous remains which have sunk from the surface. 
If the surface of peat deposits shows white patches, a slice should 
be preserved. Any light-coloured strata of low specific gravity 
either under peat or occurring by themselves among other strata 
deserve attention. 
Fungi. 
Hard woody Fungi need no special preparation, beyond keeping 
them in a dry place. Most of these are found growing on trunks 
of trees; but when a terrestrial one is met with, it should be 
dug up with care, since sometimes such forms spring from under- 
ground tuberous bodies. 
It is not possible to make satisfactory specimens of soft Fungi such 
as Agarics and Phalloidese in any but a dry climate. Much the best 
