CRUSTACEA, 
153 
Order PODOPHTHALMATA. 
The stalk-eyed Crustacea of St. Andrews are chiefly north¬ 
ern in type ; and though the species are not numerous, many 
are very plentifully represented. The most important forms 
here, as elsewhere, are the edible crab and the lobster. Both 
are caught in considerable numbers along the border of the 
rocks by means of the ordinary crab-pots, which are generally 
baited with fragments of grey gurnards and other fishes of 
little value. The most successful ground is off the East 
Rocks, though a very large lobster in the Museum of the 
University was procured to the north of the West Rocks. 
Some of the fishermen have an idea that if a lobster enters 
a trap first, none of the edible crabs will venture beside it, 
whereas a lobster will invade the crab-pot though a dozen of 
the former are already there. Constant attacks seem to have 
diminished the numbers of both species, and especially of the 
lobster. 1 have never seen any of the latter between tide- 
marks ; but young edible crabs are common under ledges and 
stones, and even in the sand at low water, their presence in 
the latter being recognized by a depression. The common 
shore-crab occurs everywhere along the rocky border, both 
between tide-marks and in the laminarian region. This ubi¬ 
quitous species lurks in the retired apertures and clefts amongst 
and under the rocks, especially where these have a bottom of 
soft sand or dark mud. In this it buries itself so as to retain 
moisture in the gills, while the anterior part of the carapace is 
uncovered, probably for quiet observation. In these situations 
it quite understands an attempt to capture it; and there are 
few examples, if any, in which, by seizing the crooked iron 
with its cheke, it has allowed itself to be drawn out. On the 
contrary, it endeavours to escape with much effort and consider¬ 
able agility. Even when quite invisible its presence may be 
detected by striking the rock, when the grating of the carapace 
is heard as the animal retreats. It is often to be found in 
positions which seem any thing but comfortable—amongst 
blackened and putrefying animal remains, in muddy and 
odoriferous pools tenanted by none except itself. In these 
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