VARIOUS LODGINGS 17 
colouring. Where wooden piles have been driven into the 
shore within tide-marks, the part which the water reaches 
is almost sure to be very soon attacked and taken posses- 
sion of by two or three very distinct crustaceans, the two 
constant companions being the strange amphipod Chelura 
terebrans, with a name signifying the boring claw-tail, and 
a perhaps equally mischievous isopod, known as Limnoria 
lignorum, or the Gribble. With these is frequently asso- 
ciated one of the cheliferous isopods, the species Tanais 
vittatus in England, and Tanais filum in America, not con- 
cerned, it may be, in making the excavations, but only 
using them when made. Some Amphipoda and Isopoda 
shelter themselves in sponges and some in the branchial 
sacs of Ascidians. 
Many free-living Copepoda may be obtained in rock- 
pools and by washing seaweeds, others from various Asci- 
dians. Those parasitic Copepoda, which are commonly 
known as fish-lice, may often be procured by examining 
fishes when first brought to shore, and before they have 
been prepared for display on the fishmonger’s board. New 
species of Crustacea have sometimes been discovered by the 
examination of the contents of a fish’s stomach. This 
same repository will also occasionally yield good specimens 
of already known species. 
The Cirripedes are all marine, most of them impatient 
even of brackish water, although one species, Baldnus 
improvisus, Darwin, will live contentedly for some time in 
water that is quite fresh. Several species are obtainable 
between tide-marks. Many attach themselves to the sub- 
merged sides of ships, and to other floating objects. Some 
make their home in sponges, corals, or shells, and in con- 
sequence specimens not sought for their own sake are 
frequently distributed by the commerce of which their 
dwelling-places are the more direct object. 
For the Gigantostraca collectors in England must 
content themselves either with fossil or with imported 
species. In New England, the horseshoe crab, Limulus 
polyphemus, may be had at or just below low water. 
By availing himself, then, of those Crustacea which 
