First lesson in zoology : adapted for use in schools . Fio. 77.—Mouth-parts of thepond - snail protruded, t,tongue; Ij, lateral teeth; j,jaw; r, rasp, or lingual rib-bon. Fig. 78.—Sea - snail [Sycotypus)boring into a shell. A, mouth(m) at rest, the rasp (r) retract-ed; B, mouth pressed againsta shell, r, the rasp gliding overs tendon like a pulley, and fil-ing a hole into the shell; thearrow points into the throat. slime, and where a snail walks it leaves behind it a glisten-ing slimy track, which soon dries. One can easily see how pond-snails eat, by watching themin a glass vessel of water, a
First lesson in zoology : adapted for use in schools . Fio. 77.—Mouth-parts of thepond - snail protruded, t,tongue; Ij, lateral teeth; j,jaw; r, rasp, or lingual rib-bon. Fig. 78.—Sea - snail [Sycotypus)boring into a shell. A, mouth(m) at rest, the rasp (r) retract-ed; B, mouth pressed againsta shell, r, the rasp gliding overs tendon like a pulley, and fil-ing a hole into the shell; thearrow points into the throat. slime, and where a snail walks it leaves behind it a glisten-ing slimy track, which soon dries. One can easily see how pond-snails eat, by watching themin a glass vessel of water, as they move about either ontheir backs at the surface of the water, or glide up the THE CLAM AND OTHER BIVALVED SHELL-FISH. 75 side of tte jar. The mouth continually opens aind within the mouth is a plate forming the jaw ( and 78); and also a slender rasp, armed with rows ofminute teeth, called the lingual rihbon, which grows on the tongue. By means of this rough rasp or minute saw,which can be thrust rapidly out and then withdr
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1894
