SHORES OF THE CLYDE AND FIRTH. 
115 
edge of the entrance hole, is the anemone, with its project- 
ing disc encircling its white waving tentacles ; and at the 
opposite side the cloak encircles the outer lip of a common 
black whelk, which is so neatly and firmly attached that it 
seems the termination of a complete whole. 
We have now gone the round of the construction of 
both, and the crab still shows no signs of recognising the 
cloaklet. Perhaps the quiet life of the tank has weaned 
him into indifference ; but we will try the effect of pushing 
the cloaklet a little nearer. Ah ! the movement has scared 
him to the opposite direction, but he quickly returns and 
stops short by the side of his old friend ; he then makes a 
slow circle round, as if inspecting the security of his old 
abode, and this time stopping at the mouth of the hole, he 
elevates his hinder part, and with an adroit jerk of the legs, 
launches backwards into the cavity, and in a twinkle the 
whole body follows. 
Now that the union is once more completed, we \^ ill fence 
the crab into the corner next the glass, where we can have 
a view of him through the lens. The first thing that attracts 
our attention is a strong current of water flowing in towards 
the breast of the creature immediately above the branches 
of the foot jaws. Tracing the source of the current, we find 
it to originate from the two branched arms at the roots of 
the jaws, which are plied up and down at a great velocity, 
in the same fashion as two switches in the operation of 
carpet-beating. These two arms, furnished as we have 
already described, with fringes of strong hairs, beating the 
water with such velocity, send it down through the fine hairs 
of the gills below; and each pair stopping and beginning 
alternately keep the current going, which serves the double 
purpose of feeding the respiratory organs, and sweeping 
round the chamber behind, escapes at the top with whatever 
