THE ENTOMOSTRACA OF EPPING FOREST. 207
As soon as possible after capture the various collections
made with the nets should be emptied into larger receptacles,
with additional water. The common glass jam jars are very
useful for this purpose. It is also advisable to pour some
collections, especially those made from amongst dense vegetation
and from the bottom, into shallow porcelain dishes. Many
forms become noticeable in this way which might otherwise be
passed over. In either case the collections should be carefully
examined with a pocket lens for any specimens having an
unfamiliar form or method of progression. In dealing with
bottom collections which are very muddy, as is most frequently
the case in fact, it is a good plan to wash away the finer particles
by placing some of the mud in a little sieve of silk gauze,
through which a gentle stream of clean water is allowed to pass.
This procedure often brings to light species whose presence was
previously quite unsuspected. Wet mosses can be washed in
the same way in the sieve, but I usually put them into a jar
with water, and, after beating them up vigorously with a fork or
some such implement, take out most of the pieces of moss and
await results. In a short time a number of Harpacticids, usually
Canthocamptus pygmaeus, are almost sure to be seen swimming
about, and very often also species of Cyclops, such as C. bisetosus,
and perhaps also some Alonas, A. tenuicaudis for example.
This method of washing damp mosses has given nearly all the
Epping Forest records of Canthocamptus pygmaeus and C. minutus
(Claus), and has yielded two species not found in any other way,
namely, Alona rustica and Moraria anderson-smithi.
As regards the actual examination of Entomostraca under
the microscope it is evidently necessary, if we are to deal at all
with the living animals, to have some method of preventing
them moving out of the field, and it is also essential, in order
to see some of the characters made use of at the present
day in the determination of species, to be able to use pretty high
magnifying powers and a wide-angled sub-stage condenser.
These conditions are best fulfilled in my opinion by a slightly
modified form of Rousselet's Live-box, and this is the object-
carrier I always use. The modification alluded to is simply that,
in the place of the large upper circle of comparatively thick
cover-glass, which in the original form extends completely across
the box, there is inserted a very thin annular metal plate, on the
under side and over the central opening of which, the thinnest
cover-glass obtainable can be cemented. Personally I prefer a