292, THE ANTARCTIC MANUAL. 
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 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. Algz 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 Algz should be scraped, and the scrapings sent as they are. 
The contents of the stomachs of Holothurians, Ascidians, are often 
very richin Diatoms. Dredgings and rubbish from the trawls 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. 
It is probable that minute Agarics and other Fungi will be 
found, though sparingly. 
It is not possible to make satisfactory specimens of soft Fungi 
such as Agarics in any but a dry climate. Much the best plan is 
to preserve them in fairly strong spirit, or in formalin diluted with 
from five to ten parts of water. A note of the colours should be 
made against the number in the collecting list, or on the ticket; 
and, if possible, in the case of an Agaric, the colour of the spores 
should be observed. This is best done by cutting off the pileus, and 
placing it for several hours on a sheet of paper; and the spores cast 
during that period will be found to have deposited a map of the 
gills on the paper. The colour may then be noted; and if possible 
the spore-cast should be preserved (numbered) by painting a thin 
film of gum on the reverse side of the paper, which should be thin. 
The pileus should be placed where there is no draught while casting 
its spores. 
Mycetozoa should be dried, and carefully preserved from crushing 
by fixing them in chip-boxes. 
