. Animal biology; Human biology. Parts II & III of First course in biology. Biology. MOLL USKS 105 through the burrow to the surface when the tide is in, and draws into its shell the water containing animalcules and oxygen. Oysters to the value of many millions of dollars are gath- ered and sold every year. The most valuable oyster fish- eries of the United States are in Chesapeake Bay. The young oysters, or " spat," after they attach themselves to the bottom in shallow water, are transplanted. New oyster beds are formed in this way. The beds are sometimes strewn with pieces of r
. Animal biology; Human biology. Parts II & III of First course in biology. Biology. MOLL USKS 105 through the burrow to the surface when the tide is in, and draws into its shell the water containing animalcules and oxygen. Oysters to the value of many millions of dollars are gath- ered and sold every year. The most valuable oyster fish- eries of the United States are in Chesapeake Bay. The young oysters, or " spat," after they attach themselves to the bottom in shallow water, are transplanted. New oyster beds are formed in this way. The beds are sometimes strewn with pieces of rock, broken pottery, etc., to encourage the oysters to attach themselves. The dark spot in the fleshy body of the oyster is the digestive gland, or liver. The cut ends of the tough adductor muscles are noticeable in raw oysters. The starfish is very destructive in oyster beds. Pearls are deposited by bivalves around some irritating particle that gets between the shell and the mantle. The pearl oyster furnishes most of the pearls; sometimes pearls of great value are obtained from fresh-water mussels in the United States. Name articles that are made partly or wholly of mother- of-pearl. Study of a Live Snail or -Is its body dry or moist ? Do land snails and slugs have lungs or gills? Why? How many pairs of tentacles has it? What is their relative length and position? The eyes are dark spots at bases of tentacles of snail and at the tips of the rear tentacles of slug. Touch the tentacles. What happens? Do the tentacles simply stretch, or do they turn inside. FIG. 202. — A SNAIL. /, mouth; vf, kf, feelers; e, opening of egg duct; fu, fopt; ma, mantle; lit, opening to lung; a, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bailey, L. H. (Liberty Hyde), 1858-1954. New York, The Macmillan Co.
Size: 2209px × 1131px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbiology, bookyear1910
