ioo LIFE AND HER CHILDREN. 
body in and out much as a worm does ; and some 
species have sharp hooks buried in their flesh which 
both help them in moving and in wounding those 
who attack them. But his great safeguard is his 
power of contraction. Try some day to find a sea- 
cucumber in a crevice on the sea-shore, and then 
set to work to get him out You will feel him slip 
through your fingers like an eel, as he squeezes the 
water out of his body and forces himself into a nar- 
row crack from which he cannot be dislodged with- 
out breaking the rock. There is a safety in pliability 
which is sometimes surer than a stout resistance, and 
where the prickly sea-urchin might fall a victim, the 
sea-cucumber effaces himself and escapes. 
A curious mixture he is of the savage and the 
cultivated animal. Though he gorges himself with 
sand, which seems after all but a coarse way of 
getting a living, yet his body is more delicately 
formed than that of any other prickly-skinned ani- 
mal, and this makes it all the more strange that he 
should have the power of throwing out nearly the 
whole of his inside, and yet living and growing it 
again. Sir John Dalyell found that a sea-cucumber 
which had lost its tentacles, its throat, its network of 
blood-vessels, its intestines, and its egg-sac, and had 
literally nothing left but an empty tube, lived, and in 
three or four months had regrown all the inside of 
its body. An animal which can exist like this, and 
is scarcely ever found with all its parts complete, 
because it has parted with some of them, and yet is 
healthy and strong, need surely not envy the brittle- 
star its stony case and wriggling arms, nor the sea- 
urchin its strong- box. 
