278 THE COWRIE. 



may expend its fury in vain, and may sweep away even the 

 upper part of the banks of sand, or may roll pebbles over 

 them; but, gifted with this means of retreat and protection, 

 these testacea are enabled to remain below secure and unin- 

 jured." 



HENRIETTA. 



And here is a little shell which I have often picked up. 



ESTHER. 



It is a Tellina, of which several species are found on our 

 coast. I have heard mamma often speak of a place near 

 Broadstairs, called Shellness, where these shells had accumu- 

 lated in such abundance that they might be carried away by 

 sacks full; but I have since heard that, from a change in the 

 currents, or some other cause, the shells have entirely disap- 

 peared from the place. There is also a spot not far from 

 Shellness, called Pegwell Bay, which is celebrated for the 

 number of cockles (Cardiuni} which are found there. Are 

 you aware that the common cockle (0. edule) can leap] and 

 so indeed can the pecten. 



HENRIETTA. 



No; I never heard of it before. 



ESTHER. 



They are enabled to do so by means of their expansile foot, 

 a structure which is common to a great majority of the mol- 

 lusca, the only instance, I believe, in nature, of a unipede, or 

 one-legged organisation. It serves both as a leg and as a 

 hand. By means of it, some species spin a byssus;* while 

 others use it as an auger; others as a trowel; others as their 

 organ of locomotion. > 



HENRIETTA. 



Here is the drawer with the cowries (Cypraea). How 

 beautiful they are! the only plain-looking one among them is 

 our little English species (Cypr&a stolida}. 



* See Chap. XI. 



