A REMARKABLE SHELLFISH.

Rangitikei Advocate and Manawatu Argus, Volume XXXIV, Issue 9466, 8 June 1909, Page 6

A REMARKABLE SHELLFISH.

MODEL FOR ENGINEERS. Perhaps the most extraordinary light-giving shellfish is the pbolas, or file fish. It is a bivalve; that is to say, it has two shells, which are open at both ends, and at each end is a cover which fits over the opening. The fish stays always in ones place, apparently without any Hie or movement, bat it is really & wide-awake, hungry creature. By means of the .covers to its shells ife can open and close them just when it wants to and oat of their opening it thrusts twelve long, crooked, hairy arms in search of its prey. Eight smaller arms are generally tu ked away inside the shell. The pbolas is found in all sorts of situations—sometimes at the bottom ■of the sea, sometimes lodged, shell and all, in the heart of the hardest marble, for the boring powers of the fish are truly marvellous. If yon take the pbolas out of its shell it looks like a soft, round pudding, with no instrument for borirg into even the softest substances. Its two teeth are so placed as to be nselses for the purpose; so are the covers to its shells. The implement which it nses is a broad, fleshy foot,. which issues from one end orother of its shell, and its method of boring suggested to the great engineer, Brnnel, in 1814, the way to make the Thames tunnel, and served as a model lor the machines nsed in> boring the Mount Csnls tunnel. The pbolas work thus: Fixing itself firmly by its , powerful ; foot it uses it as a oentrebit, around whioh it makes the shell revolve, the soft edges of the shell begin the perforation, whioh Is afterwards enlarged by tbe rasplike action of the rough interior. Though constantly worn down it is replaced by.a new formation from tbe animal, so that it is always kept in good oonidtion for boring.