Beginners' zoology . Fig. 207.—Paper Argonaut (female). X % { the animal is three times as long and broad as figure). Fig. 208.— Paper Argo-naut (male), x i/g. General Questions. — The living parts of the mussel are very soft, the name mollusca being derived from theLatin word mollis, soft. Why is it that the softest animals,the molluscs, have the hardest coverings? To which class of molluscs is the name acephala (head-less) appropriate .- Lamellibranchiata (platelike gills)? io8 BEGINNERS ZOOLOGY Why is a smooth shell suited to a clam and a roughshell suited to an oyster ? Why are the tur
Beginners' zoology . Fig. 207.—Paper Argonaut (female). X % { the animal is three times as long and broad as figure). Fig. 208.— Paper Argo-naut (male), x i/g. General Questions. — The living parts of the mussel are very soft, the name mollusca being derived from theLatin word mollis, soft. Why is it that the softest animals,the molluscs, have the hardest coverings? To which class of molluscs is the name acephala (head-less) appropriate .- Lamellibranchiata (platelike gills)? io8 BEGINNERS ZOOLOGY Why is a smooth shell suited to a clam and a roughshell suited to an oyster ? Why are the turns of a snailsshell so small near the centre? Why does the mussel have no use for head, eyes, or pro-jecting feelers? In what position of the valves of a musselis the hinge ligament in a stretched condition ? How doesthe shape of the mussels gills insure that the water cur-rent and the blood current are brought in close contact? The three main classes of molluscs are: the pelecypoda(hatchet-footed); gastropoda
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1921
