Qapers^ Piddocks, and Ship-worms 



145 



tension of the siphons. The Gaper burrows deeply 



into sand and mud, not for its food, but for 



safety — its flesh being prized by 



flshes. At the recess of the tide 



they are searched for by gulls, and 



if they are too near the surface 



they pay the penalty with their 



lives. Their siphons are stretched 



upward until they reach the water, 



when their mouths are opened and 



the streams set in motion : one 



downward, charged with micro- 

 scopic life to be filtered out and 



used as food ; the other, upward, 



discharges the water that has 



passed over the gills and been 



relieved of its oxygen. 



The first genus in this group is 



the Sunset-shells (Fsamviohia), of 



which four species are found in 



our seas. They have long slender 



shells, much compressed and gaping 



slightly at each end, the foot being 



usually extended as well as the 



siphons. These siphons are long, and separate ; the 



foot comparatively large; and the mantle -edges 



fringed. The popular name is due to 



the fact that the yellowish shells are 



Hinge-teeth of uiarkcd by radiating bands of red, 



the notion bemg that when a valve 



is held with the beak below these red bands present 



the appearance of beams from a sun that has just sunk 



below the horizon. The character of the cardinal 



Blunt Gaper 



