118 
ANIMAL LIFE ON THE 
ments ; but sometimes the cloak developes as rapidly as the 
crab, and the small shell is retained, as shown in the accom- 
panying illustration. 
In this case it was the common black whelk, but it served 
the two purposes for which the univalve is chosen, viz., to 
allow the crab to insert the claws of its soft hinder body 
into the interior screw passage of the shell, thereby giving 
it a purchase to withdraw itself within the cloak when 
danger approaches ; and when being dragged along the 
rough, stony bottom, to keep the cloak from wearing into 
a hole, thereby preserving the soft body from being exposed 
to the danger it otherwise would be. The foregoing sketch 
conveys to the reader only a very imperfect description of 
the intelligence, beauty, and intricacy of the mechanism of 
this creature. He is the prettiest of his race, but there are 
others equally interesting. 
Travelling along the shore, we often see in the clear 
pools of salt water, in the basins of the rocks, what appears 
to be the little yellow whelk, startled by our shadow, go 
scampering across the bottom, making for the sheltering 
alqce on the sides. These shells are often less than the size 
of a pea, but instead of the occupants being the original 
litorina, it is another branch of the same crab family as the 
above, known by the name of the bernard. From the 
occupancy of these small shells they flit from time to time, 
as the growth of the body requires, into larger ones, until 
they reach the size of the largest buckie shell. The selection 
is invariably those that have been recently occupied by the 
original inhabitant ; and if an empty one cannot be found 
at hand, a living occupant is victimised, and his garments 
appropriated. Like all others of the crab tribe, he is 
one of the great army of scavengers, whose carnivorous 
natures may be said to be the wisely-established permanent 
