34 NATURALISTS’ ASSISTANT. 
If a few of the rings be punctured so as to admit the spirit 
to the interior of the body this may be prevented. The 
spirit should also be frequently changed during the first few 
days. 
Along with the myriapods will generally be found the ter- 
restrial crustacea (Oniscid@), known under the common 
names of “ Sow-bugs”’ and “ Pill-bugs.”” ‘These should also 
be carefuly collected and preserved. These forms are 
ereatly desired as they have been almost wholly neglected 
by American naturalists and but little is known of our native 
species. Many of them, however, seem to be identical with 
those of Europe, and no one should attempt to describe them 
without access to the works of Brandt, Lereboullet, Kinahan, 
etc. 
MARINE COLLECTING. 
Every portion of the sea teems with life, which varies, not 
only according to geographical position but also with depth, 
sharacter of bottom, temperature of water, etc., etc. In 
different circumstances different methods are employed for 
collecting. 
Certain forms, principally Amphipod crustacea and shells, 
may be found on the shore much above high-water mark. 
Twice during the day the receding tide leaves a portion of 
the shore uncovered, and this portion “‘ between tide marks” 
has its peculiar fauna. For collecting here, one should 
wear rubber boots and be equipped with bottles, forceps, etc. 
There should be a considerable variety in the bottles em- 
ployed. A good idea is to have four or six large jars with 
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