AND PRESERVING PLANTS. 131 



labelled with locality, approximate height above sea-level, date, and 

 character of the water, Avhether 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 sand-grains is often small. Rock-pools between tide-marks 

 should be examined, and sloping or horizontal rock surfaces scraped. 

 Algae 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 Algae 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 Phalloideoe in any but a dry climate. Much the best 



