ntents by the mouth, or we may have
a contrivance by which the bottom of the bag is made to unlace. The
first plan is the simpler and the one more usually adopted; the second
has the advantage of letting the mass slide out more smoothly and
easily, but the lacing introduces rather a damaging complication, as it
is apt to loosen or give way. Any objects visible on the surface of the
heap are now carefully removed, and placed for identification in jars or
tubs of sea-water, of which there should be a number secured in some
form of bottle basket, standing ready. The heap should not be much
disturbed, for the delicate objects contained in it have already been
unavoidably subjected to a good deal of rough usage, and the less
friction among the stones the better.

_Examination of the Catch. Sifting._--The sorting of the catch is
facilitated by sifting. The sieves used in early English expeditions
were of various sizes and meshes, each sieve having a finer mesh than
the sieve smaller than itself. In use the whole were put together in the
form of a nest, the smallest one with the coarsest mesh being on top. A
little of the dredge's contents were then put in the top sieve, and the
whole set moved gently up and down in a tub of sea water by handles
attached to the bottom one. Objects of different sizes are thus left in
different sieves. A simple but effective plan is to let the sieves of
various sized mesh fit accurately on each other like lids, the coarsest
on top, and to pour water upon material placed on the top one. In the
United States Bureau of Fisheries ship "Albatross" these sieves are
raised to form a table and the water is led on them from a hose: the
very finest objects or sediments are retained by the waste water
escaping from a catchment tub by muslin bags let into its sides. Any of
these methods are preferable to sifting by the agitation of a sieve hung
over the side, as in the last anything passing through the sieve is gone
past recall.

_Preservation of Specimens._--The preservation of specimens will of
course depend on the purpose for which they are intended. For
microscopic observation formaldehyde has some advantages. It can be
stored in 40% solution and used in 2%, thus saving space, and it
preserves many animals in their colours for a time: formalin
preparations do not, however, last as well as do those in spirit. The
suitable fluids for various histological inquiries are beyond the scope
of the present art