118 POPULAE, BRITISH COXCHOLOGY. 



have the creeping disc large and powerful ; the mouth has 

 a pair of horny jaws, and a long ribbon-shaped tongue, armed 

 with teeth. When the animal is removed from its shell, a 

 muscular impression is seen, which surrounds the inner 

 surface, excepting at the part where the head lies, which 

 is not itself attached, but can be protruded. The shell is 

 conical. The genera are — 



I. Patella. — The point of the cone is not at all curved, but 

 it is at the shorter end of the shell; and turning it over, 

 we find the space for the head towards the same, which 

 is therefore the front. The animal has two needle- 

 shaped tentacles on a distinct head, with an eye on a 

 swelling near the base of each ; the edge of the mantle 

 which lines the shell is hairy. 

 Supported on a wide base, the strong pyramidal shell is 

 held firmly in its position by the pressure of the air on the 

 vacuum formed by the sucker-foot. The wildest waves may 

 rage, the heaviest stones be hurled against it, without alter- 

 ing its position or destroying the protection it aftbrds to its 

 owner. Yet the creature can move, and it is said can even 

 raise his shell and spring to a considerable distance ! 



" Well, suppose it a bounce, sure a poet may try- 

 By a bounce now and then to get courage to fly." 



