NOTES AND MEMORANDA. 
369 
“ In the case of tidal marine pools and small fresh- water ponds, such 
as may easily he fished from the edge, a common ring net fitted with a 
muslin bag and attached to the end of a walking-stick will answer 
every purpose. This may be worked to and fro amongst the weeds or 
in the clear water, and the results, when cleared from coarse debris 
and extraneous materials, may either be j^Rt at once into spirit, or, if 
it is wished to keep the Entomostraca alive, into water, fresh or 
salt, as the case may be. Marine surface-swimmers may be taken 
in a similar way by working the net from the side of a boat, or a 
tow net may be thrown over and attached to the boat by a cord. 
A tow net put overboard from a vessel anchored for the night 
in a tideway will often be found in the morning to have made good 
captures. And it may be noted that surface net gatherings made 
during the hours of dusk or darkness are commonly of much greater 
interest than those taken in daytime ; it seems certain that many 
marine Crustacea which are found near the surface at night recede 
towards the bottom on the ajiproach of daylight. . . . The washing of 
fronds and roots of Laminarise, which may be dragged up by means 
of the hooked gra2mels used on many coasts by kelp-burners, often 
affords multitudes of Copepoda. The weeds should be washed by 
agitation in a large tub of sea- water, and when the oj)eration is com- 
pleted, the water, after being allowed sufficient time — a few seconds 
only — for the subsidence of coarse material, is to be poured off 
through a muslin net, on which the Copej)oda, and probably numerous 
other swimming animalcula, will be intercej)ted. These may be 
cleaned while in the net by repeated douches of sea-water. The pro- 
ducts of the dredge, sand, mud, gravel, shells, &c., should be treated 
in a similar manner before being thrown overboard. I have no doubt 
that this method of procedure offers by far the best chance of extended 
acquaintance with microscojnc life of the sea-bed, and that numberless 
new species and interesting forms of life may be discovered by its 
means. 
The preservation of specimens is probably best effected by alcohol 
in the form of rectified or methylated spirit, but this agent has the 
disadvantages of destroying many colours, and of rendering the 
animals opaque by coagulating their albuminous tissues. Still, 
among the numerous solutions which have from time to time been 
recommended, none are on the whole so convenient or efficient. 
Perhaps the next best is a solution of chloral hydrate (twelve grains 
to a fluid ounce) in camphor water. As microscopic preparations, 
Copepoda are best mounted in some gelatinous medium containing a 
very small quantity of glycerine. Treated in this way, mountings 
will keep in perfect condition for many years — eternally for anything 
I know to the contrary — without the trouble of cementing round the 
edges of the glass cover. Before dissecting Copepoda for micro- 
scopic examination, they should be macerated for a few hours in a 
solution of caustic potash ; the fatty and granular tissues are by this 
means removed and the details of structure rendered clearly visible ; 
the dissection is easily performed under the microscope with fine 
needles, either with or without the help of an erector.” 
